Space stations past and present

The International Space Station (ISS) is now 20 years old. In this post I’ll talk about the history of the ISS and other space stations, and I’ll also touch on some of the politics involved.

Image from NASA

 

Early space stations

 

Although America was the first country to put a man on the Moon, the Soviet Union led the way in long duration spaceflights and was the first country to launch a space station, where humans could  live and work for longer periods of time. Before the advent of space stations, astronauts were confined to cramped space capsules.  Continue reading “Space stations past and present”

The International Space Station updated

Since the publication of the original post on 2 August 2018, NASA have delayed the planned launch dates for the American spacecraft to carry astronauts to and from the International Space Station. In my original post I referred to the Boeing and SpaceX spacecraft taking astronauts this year, which was an ambitious target, bearing in mind that it was already August and neither spacecraft had flown an unmanned mission! Perhaps unsurprisingly the planned launch dates have slipped into 2019 and I have updated my post to reflect this.

Original post below——

This year marks the 20th anniversary of the International Space Station (ISS).

Image from NASA.

The first module of the ISS, called Zarya, was launched by a Russian rocket back in November 1998. Zarya was not an inhabitable module and its function was to provide electrical power, storage and propulsion to the ISS during the initial stages of assembly. Interesting the word ‘Zarya’ is Russian for sunrise and Zarya, being the first step in building the ISS, was to signify a new dawn in international cooperation.

The first module of the ISS called Zarya – Image from NASA  Note: the solar panels shown are no longer used and have been retracted.

The ISS has a modular design and in the twenty years since Zarya numerous modules have been added, gradually growing it into the structure we see today.  A key milestone was achieved on 2 November 2000 when a Russian Soyuz spacecraft bought the first crew to the ISS. The ISS has been manned ever since that date, providing a permanent human presence in space. The current crew of the ISS is known as Expedition 56 and consists of: three Americans, two Russians and one German.

Mission patch for Expedition 56 – Image from NASA

Key role of the Space Shuttle

Image from NASA

The American Space Shuttle, which flew between 1981 and 2011, was key to building the ISS. The Shuttle had the capacity to take large modules in its cargo bay and crews of up to six astronauts on assembly missions. Many of these missions involved extended spacewalks. Indeed, without the Space Shuttle it would not have been possible to build the ISS. In fact, post 1998, construction of the ISS became the almost the entire focus of the shuttle programme. This is illustrated by the statistic that of the 43 space Shuttle Missions flown after the launch of Zarya, 38 (89%) of them went to the ISS to deliver a new module and components to the station, bring fresh supplies or to bring fresh crew to the ISS and return the old crew to Earth.

The ISS today

The ISS is shown in the image at the top of this post. Although some minor construction missions are planned later this year and in 2019, the components to be added are relatively small and construction is essentially complete. The ISS is a very flat structure. It is 73 metres long and a maximum of 109 meters wide, but its maximum depth is only a few metres. It has a mass of 420 tons. Its most noticeable feature are the eight separate sets of solar panels, which look like giant wings and in total generate up to 90 kilowatts of electric power (NASA 2018).

The orbit of the ISS 

The ISS orbit is almost perfectly circular, just over 400 km above the Earth’s surface. At this altitude, although it is classified as being in space, which begins at an altitude of 100 km, (see my previous post), here are sufficient traces of the Earth’s atmosphere to cause the ISS to lose energy as it moves against the air resistance caused by this very thin gas. This causes the ISS to very gradually spiral down to Earth as it loses a small amount of energy on each orbit. The distance a satellite drops in altitude is known as its orbital decay and for the ISS is 2 km per month, which works out at about 70 metres per day. If nothing were done the ISS would gradually return to Earth within a few years and as it hit the thicker atmosphere it would disintegrate. To prevent this happening the ISS has a set of thrusters, which are fired periodically to boost it into a higher orbit. Visiting spacecraft also fire their rocket motors to the same effect.

Because it is both large and travels in a low orbit, the ISS can be easily seen from Earth. It is visible to the naked eye as a slow-moving, bright white dot. Its brightness is due to sunlight reflecting off its solar panels. The best time to see it is either after sunset or before sunrise, when the station remains sunlit, but the sky is dark.  This is shown in the diagram below.

The ISS takes about 90 minutes to complete an orbit. As it moves around its orbit:

  • the ISS is visible at night between sunset, point A, and when it disappears behind the Earth’s shadow, point B;
  • between points B and C the ISS is in the Earth’s shadow it receives no direct sunlight and cannot be seen;
  • between point C, when it emerges from the Earth’s shadow, and point D, sunrise, the ISS is visible;
  • between points D and A, the ISS cannot be easily seen against the brightness of the daytime sky.

Because of its size, the ISS is the brightest artificial object in the sky and has a similar brightness when overhead to the planet Venus.

 

Research at the ISS

A good deal of research is carried out at the ISS. This is described in more detail at the following website  https://www.nasa.gov/mission_pages/station/research/overview.html.  Much of this research is based upon the fact that that the strength of gravity is very close to zero in the ISS. This is known as micro-gravity and the only place it is possible to create a micro-gravity environment, for longer than a few minutes, is in space. Some examples of this research are given below.

  • Fluids can be almost completely combined in micro-gravity, so physicists can investigate fluids that do not mix well on Earth.
  • In micro-gravity environment combustion occurs differently. Flames have a spherical shape. In the diagram below, the candle on the left is in normal gravity, whereas the candle on the right is in micro-gravity.

Image from NASA

  • Research has been carried out as to how plants develop in micro-gravity. Interestingly, results have shown that plants use light rather than gravity to determine which direction is ‘up’.

But perhaps the most interesting area of research are the effects on the human body of spending long periods on time in near weightlessness. This area is important, because in the next few decades when astronauts travel to Mars they will have to spend at least six months in zero gravity when travelling to the red planet and a further six months on the return journey. Some of the effects which have been found are.

  1. Without any weight to work against, muscles gradually will get smaller and lose their strength. This includes the heart muscle.
  2. Fluid shifts around the body causing fluid pressure in the brain to increase.
  3. One of the most serious problems is that, without gravity, a strong skeleton is not needed to support the body. Studies have shown that astronauts lose 1-2 % of their bone mass for each month of weightlessness; the calcium from their bones is excreted in their urine. So much calcium may be lost that it can cause kidney stones.

Research on the ISS has shown that to retain their muscle mass, and ensure their heart stays in good condition, astronauts need to spend many hours a day exercising.  Because there is no weight for their muscles to work against, astronauts often spend a large fraction of the day running on a treadmill, using elastic harnesses to provide resistance.

However, nothing has been discovered which can prevent the loss of bone density. The rate of bone loss continues at 1-2% per month and does not level off after long durations in space. After more than two years in low gravity, astronauts’ bones would be so weak they would easily fracture and would be unable to support their weight then they returned to Earth. This may be a limiting factor for how long humans can spend in zero gravity environments, especially since it takes a significant time for the bone density to return to normal.

A further limiting factor is that on long duration spaceflights astronauts will be exposed to high doses of radiation. This can cause genetic damage making the astronauts more prone to cancer in later life.

Taller Astronauts

Spending time in a microgravity environment causes the spine to elongate. On Earth, gravity keeps the vertebrae in place by constantly pushing them together. But without gravity, the vertebrae will naturally expand slightly, causing a person to become taller.

 

Typically, astronauts in space can grow up to three percent of their original height. For example, in 2016 when Scott Kelly came to Earth after spending nearly a year in space he was 2 inches (5 cm) taller. However, this gain in height is only temporary. When under the effects of gravity again astronauts return to their original height.

Scott Kelly – Image from NASA

Getting to and from the ISS

Since the end of the Shuttle programme the only way astronauts can get to and from the ISS is by the Russian Soyuz spacecraft, a point worth remembering now that relations between the US and Russia are rather strained.  Soyuz was first flown in 1967 and its design has changed little since then. Like the Apollo spacecraft which took astronauts to the Moon, it is a single use spacecraft.  Currently NASA pay $70 million for each astronaut who flies in the Soyuz spacecraft (Wall 2013), which enables the Russian space agency to make a significant profit.

In the next few years US spacecraft should return to space.  Rather than build a new craft to fly crew to and from the ISS, NASA administer a US-government funded programme called Commercial Crew Development (CCDev). After a lengthy evaluation process NASA announced in September 2014 that Boeing and SpaceX had received contracts to provide crewed launch services to the ISS.

When the final decision was made, NASA hoped that the winning companies would be able to launch manned missions to the ISS by 2017. However, perhaps unsurprisingly, there have been numerous delays in the development of both spacecraft and the launch dates have slipped.

According to the current launch schedule (https://www.nasa.gov/launchschedule/ ), the target dates for unmanned test flights are:

  • ‘late 2018 / early 2019’ for the Boeing spacecraft
  • ‘November 2018’ for SpaceX.

However, it must be be pointed out that they are only target dates and may slip further.

If there are no further delays and these test flights do take place as planned and are successful, then in April 2019 the SpaceX Dragon v2 spacecraft will be the first American spacecraft to carry astronauts into orbit since the retirement of the Space Shuttle. This will be followed by the Boeing CT100, shown below, in the middle of the year.

The Boeing CT-100 Starliner Space Capsule – image from NASA. In lmid 2019 this spacecraft may take astronauts to and from the ISS.

Next post

I hope you’ve enjoyed this post. In my next post I’ll talk about the costs of the space station, international cooperation in space and how I see the future of the ISS.

 

 

NASA (2018) International Space Station facts and figures, Available at: https://www.nasa.gov/feature/facts-and-figures (Accessed: 30 July 2018).

 

Wall, M (2013) NASA to pay $70 Million a seat to fly astronauts on Russian spacecraft,Available at: http://www.space.com/20897-nasa-russia-astronaut-launches-2017.html(Accessed: 30 July 2018)

 

 

The International Space Station

Note 10 September 2018.  The information in the section ‘Getting to and from the ISS’ has been superseded by information in the updated version of this post.

This year marks the 20th anniversary of the International Space Station (ISS).

Image from NASA.

The first module of the ISS, called Zarya, was launched by a Russian rocket back in November 1998. Zarya was not an inhabitable module and its function was to provide electrical power, storage and propulsion to the ISS during the initial stages of assembly. Interesting the word ‘Zarya’ is Russian for sunrise and Zarya, being the first step in building the ISS, was to signify a new dawn in international cooperation.

The first module of the ISS called Zarya – Image from NASA  Note: the solar panels shown are no longer used and have been retracted.

The ISS has a modular design and in the twenty years since Zarya numerous modules have been added, gradually growing it into the structure we see today.  A key milestone was achieved on 2 November 2000 when a Russian Soyuz spacecraft bought the first crew to the ISS. The ISS has been manned ever since that date, providing a permanent human presence in space. The current crew of the ISS is known as Expedition 56 and consists of three Americans, two Russians and one German.

Mission patch for Expedition 56 – Image from NASA

Key role of the Space Shuttle

Image from NASA

The American Space Shuttle, which flew between 1981 and 2011, was key to building the ISS. The Shuttle had the capacity to take large modules in its cargo bay and crews of up to six astronauts on assembly missions. Many of these missions involved extended spacewalks. Indeed, without the Space Shuttle it would not have be possible to build the ISS. In fact, post 1998, construction of the ISS became the focus of the shuttle programme. This is illustrated by the statistic that of the 43 space Shuttle Missions flown after the launch of Zarya, 38 (89%) of them went to the ISS to deliver a new module and components to the station, bring fresh supplies or to rotate crew.

The ISS today

The ISS is shown in the image at the top of this post. Although a few more construction missions are planned later this year and in 2019, the components to be added are relatively small and construction is essentially complete. The ISS is a very flat structure. It is 73 metres long and a maximum of 109 meters wide, but its maximum depth is only a few metres. It has a mass of 420 tons. Its most noticeable feature are the eight separate sets of solar panels, which look like giant wings and in total generate up to 90 kilowatts of electric power (NASA 2018).

The orbit of the ISS 

The ISS orbit is almost perfectly circular, just over 400 km above the Earth’s surface. At this altitude, although it is classified as space (which begins at an altitude of 100 km, see my previous post ), there are sufficient traces of the Earth’s atmosphere to cause the ISS to lose energy as it moves against the air resistance caused by this very thin gas. This causes the ISS to very gradually spiral down to Earth as it loses a small amount of energy on each orbit. The distance a satellite drops in altitude is known as its orbital decay and for the ISS is 2 km per month, which works out at about 70 metres per day. If nothing were done the ISS would gradually return to Earth within a few years and as it hit the thicker atmosphere it would disintegrate. To prevent this happening the ISS has a set of thrusters, which are fired periodically to boost it into a higher orbit. Visiting spacecraft also fire their rocket motors to the same effect.

Because it is both large and travels in a low orbit, the ISS can be easily seen from Earth. It is visible to the naked eye as a slow-moving, bright white dot. Its brightness is due to sunlight reflecting off its solar panels. The best time to see it is either after sunset or before sunrise, when the station remains sunlit, but the sky is dark.  This is shown in the diagram below.

The ISS takes about 90 minutes to complete an orbit. As it moves around its orbit:

  • the ISS is visible at night between sunset, point A, and when it disappears behind the Earth’s shadow, point B;
  • between points B and C the ISS is in the Earth’s shadow it receives no direct sunlight and cannot be seen;
  • between point C, when it emerges from the Earth’s shadow, and point D, sunrise, the ISS is visible;
  • between points D and A, the ISS cannot be easily seen against the brightness of the daytime sky.

Because of its size, the ISS is the brightest artificial object in the sky and has a similar brightness when overhead to the planet Venus.

 

Research at the ISS

A good deal of research is carried out at the ISS. This is described in more detail at the following website  https://www.nasa.gov/mission_pages/station/research/overview.html.  Much of this research is based upon the fact that that the strength of gravity is very close to zero in the ISS. This is known as microgravity and the only place it is possible to create a microgravity environment for longer than a few minutes is in space. Some examples of this research are given below.

  • Fluids can be almost completely combined in microgravity, so physicists can investigate fluids that do not mix well on Earth.
  • In microgravity environment combustion occurs differently. Flames have a spherical shape. In the diagram below, the candle on the left is in normal gravity, whereas the candle on the right is in microgravity.

Image from NASA

  • Research has been carried out as to how plants develop in microgravity. Interestingly, results have shown that plants use light rather than gravity to determine which direction is ‘up’.

But perhaps the most interesting area of research are the effects on the human body of spending long periods on time in weightlessness. This area is important, because in the next few decades when astronauts travel to Mars they will have to spend at least six months in zero gravity when travelling to the red planet and a further six months on the return journey.

  • Without any weight to work against, muscles gradually will get smaller and lose their strength. This includes the heart muscle.
  • Fluid shifts around the body causing fluid pressure in the brain to increase.
  • One of the most serious problems is that, without gravity, a strong skeleton is not needed to support the body. Studies have shown that astronauts lose 1-2 % of their bone mass for each month of weightlessness; the calcium from their bones is excreted in their urine. So much calcium may be lost that it can cause kidney stones

Research on the ISS has shown that to retain their muscle mass, and ensure their heart stays in good condition, astronauts need to spend many hours a day exercising.  Because there is no weight for their muscles to work against, astronauts often spend a large fraction of the day running on a treadmill, using elastic harnesses to provide resistance.

However, nothing has been discovered which can prevent the loss of bone density. The rate of bone loss continues at 1-2% per month and does not level off after long durations in space. After more than two years in low gravity, astronauts’ bones would be so weak they would easily fracture and would be unable to support their weight then they returned to Earth. This may be a limiting factor for how long humans can spend in zero gravity environments, especially since it takes a significant time for the bone density to return to normal.

A further limiting factor is that on long duration spaceflights astronaut would be exposed to high doses of radiation. This can cause genetic damage making the astronauts more prone to cancer in later life.

Taller Astronauts

Spending time in a microgravity environment causes the spine to elongate. On Earth, gravity keeps the vertebrae in place by constantly pushing them together. But without gravity, the vertebrae will naturally expand slightly, causing a person to become taller.

 

Typically, astronauts in space can grow up to three percent of their original height. For example, in 2016 when Scott Kelly came to Earth after spending nearly a year in space he was 2 inches (5 cm) taller. However, this gain in height is only temporary. When under the effects of gravity again astronauts return to their original height.

Scott Kelly – Image from NASA

Getting to and from the ISS

Since the end of the Shuttle programme the only way astronauts can get to and from the ISS is by the Russian Soyuz spacecraft, a point worth remembering now that relations between the US and Russia are rather strained.  Soyuz was first flown in 1967 and its design has changed little since then. Like the Apollo spacecraft which took astronauts to the Moon, it is a single use spacecraft. The astronauts return to Earth in a small capsule which has a heat shield to protect it during the most dangerous part of the mission, re-entry into the Earth’s atmosphere. Currently NASA pay $70 million for each astronaut who flies in the Soyuz spacecraft (Wall 2013), which enables the Russian space agency to make a significant profit.

In the next few years US spacecraft should return to space.  Rather than build a new craft to fly crew to and from the ISS, NASA administer a US-government funded programme called Commercial Crew Development (CCDev). After a lengthy evaluation process NASA announced in September 2014 that Boeing and SpaceX had received contracts to provide crewed launch services to the ISS.

When the final decision was made, NASA hoped that the winning companies would be able to launch manned missions to the ISS by 2017. However, perhaps unsurprisingly, there have been numerous delays in the development of both spacecraft and the launch dates have slipped.

According to the current launch schedule (https://www.nasa.gov/launchschedule/ ), the target dates for unmanned test flight of both spacecraft are actually this month, August 2018, although precise date haven’t been specified. If there are no further delays and these test flights do take place this month and are successful, then in November 2018 the Boeing CT 100 spacecraft will be the first American spacecraft to carry astronauts into orbit since the retirement of the Space Shuttle. This will be followed by the SpaceX Dragon v2 the following month.

 

Next post

I hope you’ve enjoyed this post. In my next post I’ll talk about the costs of the space station, international cooperation in space and how I see the future of the ISS.

 

 

NASA (2018) International Space Station facts and figures, Available at: https://www.nasa.gov/feature/facts-and-figures (Accessed: 30 July 2018).

 

Wall, M (2013) NASA to pay $70 Million a seat to fly astronauts on Russian spacecraft,Available at: http://www.space.com/20897-nasa-russia-astronaut-launches-2017.html(Accessed: 30 July 2018)

 

 

Methane on Mars

I was very excited to read about the discovery published last week by NASA’s Curiosity rover of the seasonal variation in the amount of methane in Mars’ atmosphere. Curiosity found that the average methane concentration varied from 0.24 parts per billion (ppb) in the northern hemisphere winter to around 0.65 ppb in the summer.

This was widely reported in the world’s media e.g.the New York Times.The interesting fact is that, on Mars, methane should have a very short lifetime because it is destroyed by ultraviolet light from the Sun. The presence of any methane in Mars’ atmosphere means that there must be some process, as yet unknown, continually producing it.  On Earth nearly all methane is biological in origin and is generated by microorganisms as a waste product. The seasonal variation in methane in Mars’s atmosphere is certainly consistent with life, but there may be other non-biological processes making this methane.

A joint mission between the European Space Agency (ESA) and the Russian space agency, called the TGO has just started scientific operations and may shed more light on the origin of this methane. I’ve therefore attached an updated version of my earlier post about this spacecraft.

————–

Two years ago on 14 March 2016 the ExoMars Trace Gas Orbiter (TGO) spacecraft was launched from Baikonur, Kazakhstan on a journey to Mars. The purpose of its mission is to study how the distribution of the gas methane varies with location on the planet’s surface and over the course of time.

Trace Gas orbiter

Image from ESA

What is the significance of methane on Mars?

Compared to the Earth, Mars has a very thin atmosphere. Its surface pressure is only 0.6% of that of the Earth. The atmosphere mainly consists of carbon dioxide. However, it also contains a small amount of methane, around 0.5 parts per billion. This is a puzzle to scientists because the ultraviolet light from the Sun should break up any methane within 600 years, and Mars is 4.5 billions old. Therefore there must be some process occurring which is constantly replenishing the methane.

Mars NASA

Mars- Image from NASA

There are various possibilities for the origin of this methane. One is that it is released by geological processes such as volcanoes or a chemical process occurring within rocks called serpentinisation. This is not as exciting as it sounds (no snakes, I’m afraid) – it is simply a slow chemical reaction between olivine (a mineral found on Mars) carbon dioxide and water which can produce methane.  Another is that there is a large reservoir of methane locked away in the ice below the Martian surface and as the temperature varies some of the ice may melt, thus releasing the methane into the atmosphere.

A fascinating possibility is that the methane is created by microorganisms below the planet’s surface.  On Earth more than 90% of methane in the atmosphere is produced by living organisms (ESA 2014). There are over 50 species of microorganisms known as methanogens that live off organic matter and produce methane as a waste product.  These microorganisms are found not only in wetlands (producing what is known as marsh gas) and in the soil but also in the guts of many animals such as cows and humans.  At the risk of sounding somewhat vulgar, the methane gas escapes from both cattle and ourselves in the form of flatulence.

methanogen

Methanogens

What will the TGO measure?

The TGO will measure how the methane content of Mars’s atmosphere varies with space and time. It will also be able to measure the concentration of other gases such as sulphur dioxide (which on Earth is normally associated with volcanic activity) and organic compounds such as ethane, methanol and formaldehyde (which on Earth are produced by living organisms).  Although the TGO won’t be able to say for definite what the sources of the methane found on Mars are, if the concentration of methane were found to vary with the seasons and also if methane were found in conjunction with other organic chemicals it would point towards a biological origin.

How long with the mission be?

The TGO is a joint mission between the European Space Agency (ESA) and the Russian Space Agency (Roscosmos).  The mission is described in more detail on the ESA website  (2018).  It arrived at Mars in October 2016 and was initially placed in a high elliptical orbit around the planet. It took until March 2018 to gradually manoeuvre into the intended orbit and, now it is in the correct position, will spend the next five years mapping the methane distribution. This is a low circular orbit only 400 km from the planet’s surface. The orbit is inclined at an angle of 74 degrees to Mars’s equator. This high inclination enables the spacecraft to see most of the planet’s surface.

The high inclination of the TGO’s orbit means that, as the planet rotates, all area of Mars between latitudes -74 degrees South and 74 degrees North will at some stage be directly below the TGO.

Footnote- Schiaparelli

When the TGO arrived at Mars, it it deployed a small lander called Schiaparelli. This was an ‘add on’ to the main mission and was only designed to operate for a week on the Martian surface. Schiaparelli was intended to measure the wind speed and direction, humidity, pressure and surface temperature, and determine the transparency of the atmosphere. Sadly, when Schiaparelli arrived in the upper regions of the Martian atmosphere, a parachute to slow it down failed to open properly and it crashed into the surface at thousands of km/h and will was destroyed by the impact.

References

ESA (2014) The enigma of methane on Mars, Available at:http://exploration.esa.int/mars/46038-methane-on-mars/ (Accessed: 20 March 2016).

ESA (2018) Robotic exploration of Mars, Available at:http://exploration.esa.int/mars/46124-mission-overview/ (Accessed: 12 June 2018)

American manned spaceflight in 2018?

As readers of a previous post will know, since the retirement of the Space Shuttle in July 2011, America has been unable to put any astronauts into orbit around the Earth. Instead, it has been reliant on the Russian Soyuz spacecraft to ferry astronauts to and from the International Space Station (ISS). This situation may finally change in 2018; in the final two months of the year there are two missions tentatively planned to take astronauts to the ISS on American spacecraft. Interestingly, as a result of a change in space policy by the Obama administration eight years ago, both these missions will be in spacecraft designed and built by private companies, rather than NASA.

The Boeing CT-100 Starliner Space Capsule – image from NASA. In late 2018 this spacecraft may take astronauts to and from the ISS.

In a major speech in 2010, US President Obama announced a major shift in the function of NASA in American human space flight.

By buying the services of space transportation — rather than the vehicles themselves — we can continue to ensure rigorous safety standards are met. But we will also accelerate the pace of innovations as companies — from young startups to established leaders — compete to design and build and launch new means of carrying people and materials out of our atmosphere. ….

Some have said, for instance, that this plan gives up our leadership in space by failing to produce plans within NASA to reach low Earth orbit, …. But we will actually reach space faster and more often under this new plan, in ways that will help us improve our technological capacity and lower our costs, which are both essential for the long-term sustainability of space flight.’

(White House press release 2010)

Image from Wikimedia Commons

So, rather than build its own spacecraft to replace the Space Shuttle, NASA awarded grants to private companies to support research and development into human space flight. The program had a number of phases. In the first phase five companies were awarded grants to partially fund the research and development of the key technologies and capabilities that could ultimately be used in human space transportation systems. In the next phases, NASA awarded further grants to four companies to develop spacecraft that could send to astronauts to the ISS after the Space Shuttle’s retirement.

Image from NASA

After another selection process, in 2014 NASA made the final decision that the winners of the contracts for up to six crewed flights to transport astronauts to and from the ISS were as follows.

  • Boeing – They were given a contract worth up to $4.2 billion, to transport astronauts on their CT-100 Starliner spacecraft.
  • Space X –  This is a company set up by Elon Musk, the co-founder of Paypal. They were given a contract worth up to $2.6 billion to transport astronauts on their Dragon V2 – pictured below.

For more details see the reference below (NASA 2014).

 

DragonV2

 The Dragon V2 Spacecraft – Image from NASA 

When the final decision was made it was hoped that the winning companies would be able to launch manned missions to the ISS by 2017. However, perhaps unsurprisingly, there have been numerous delays in the development of both spacecraft and the launch dates have slipped.

According to the current launch schedule (https://www.nasa.gov/launchschedule/ ) , the target dates for unmanned test flight of both spacecraft are August 2018, although an exact date hasn’t been specified. If there are no further delays and these test flights do take place in August and are successful, then in November 2018 the Boeing CT 100 spacecraft will be the first American spacecraft to carry astronauts into orbit since the retirement of the Space Shuttle. This will be followed by Dragon v2 the following month.

Opportunities for space tourism

The contract terms are that both companies will charge NASA around $60 million for each seat on a flight to the ISS. This is slightly cheaper than the amount it pays to the Russian space agency for a seat aboard Soyuz. The real boost is that, rather than the money going to the Russian space agency, it will go to American companies, boosting American high technology industries and creating American jobs.

Once they have fulfilled their contractual commitments to NASA, both companies are free to sell to additional spare capacity to space tourists willing to spend around $60 million dollars for a flight into orbit. This would be a very different type of space tourism than that offered by Virgin Galactic where customers will pay $250,000 for a three hour flight of which only two minutes are above an altitude of 100 km, which is defined as the boundary of space.

.Virgin Galactic rocket motor

Artist impression of Virgin Galactic’s SpaceShipTwo accelerating into Space – Image from Virgin Galactic

In February 2017 Elon Musk made the bold announcement that two individuals, who I must assume are extremely wealthy, had approached him and put down a ‘substantial deposit’ for a private spaceflight around the Moon in the Dragon v2 capsule.  At the time this was widely reported in the media e.g.  https://www.theguardian.com/science/2017/feb/27/spacex-moon-private-mission-2018-elon-musk

Musk refused to say who the individuals were or how much they had paid, but I would expect that the total cost of the spaceflights will be over $100 million dollars each.  To achieve enough speed to escape from the Earth’s gravity and reach the Moon the mission would use SpaceX’s new booster, the Falcon Heavy rocket, which was first launched in February 2018.

The Falcon Heavy launcher – image from Wikimedia Commons. This launcher could be used to launch a Dragon V2 spacecraft around the Moon

The spaceflight would be likely to follow a path known as free-return trajectory. I’ll talk about free-return trajectories in a later post, but essentially the idea is that it uses the Moon’s gravity to slingshot the spacecraft back to Earth, thus minimising the amount of fuel needed.

A typical free-return trajectory – image from Wikimedia Commons.

The original announcement said the spaceflight would be in 2018. However, according  to reports earlier this month, like this one, Elon Musk has said that the mission will be delayed because SpaceX will be focussing its effort on developing a new launcher with twice the thrust of Falcon Heavy. This is currently called the ‘Big Falcon Rocket’, but  I expect it it will be given a different name as the project progresses.

Therefore, I think that although this spaceflight will take place, it is unlikely to happen before 2020. However when it does occur I am sure that many people will follow it with great excitement. It will be the first time that humans have ventured outside the low Earth orbit since the last Apollo moon-flight in 1972.

Footnote – the Orion spacecraft

Even though NASA is now commissioning private companies to transport astronauts into low Earth orbit, it has not abandoned developing its own manned spacecraft altogether. It is currently developing the Orion spacecraft and a new launcher called the Space Launch System. Around 2023-5 the spacecraft is expected to take its first crew into orbit around the Earth, and it will have the capability take a crew of up to four beyond low Earth Orbit, perhaps on a mission around the Moon or to a nearby asteroid.


I hope you have enjoyed this post. To find out more about the Science Geek’s blog, click here or at the Science Geek Home link at the top of this page.


References

NASA (2014) NASA chooses American companies to transport U.S. astronauts to International Space Station, Available at: https://www.nasa.gov/press/2014/september/nasa-chooses-american-companies-to-transport-us-astronauts-to-international (Accessed: 7 February 2018).

The White House (2010) Remarks by the president on space exploration in the 21st century, Available at: https://www.nasa.gov/news/media/trans/obama_ksc_trans.html(Accessed: 6 February 2018).

 

A Christmas gift from The Science Geek 2017

 

Christmas is almost upon us. Once again I’m offering my e-books for free during the first five days of December!  Just call me Father Christmas :-).

Is Anyone Out There?” is about the likelihood of there being extraterrestrial intelligent life.  It is based on a number of posts from my blog.  For readers based in the UK the book is available to download from Amazon in Kindle format by clicking here and for readers in the US by clicking here. If you’re based outside the UK or US , see the notes at the end of the post.

Is Anyone Out There Cover

The Moon” is also based on a series of posts from my blog and you can guess what it is about.  UK readers download here, US readers here and anyone else please see the notes below.

Moon Cover

How to download the books if you’re based outside the UK or US.

There are threeways of doing this.

Option 1 if you go into the Amazon Kindle store and search for “The Science Geek” as the author you should find my books.

Option 2  I have created a page on my website where you will be able to download either of books for free.
https://thesciencegeek.org/e-books/

I’ll put them there until at least the end of the year.

Option 3  If your country is listed below, I have added some links  to allow you to download the books by just clicking on the link for your country.

Is There Anyone Out There?

Australia http://www.amazon.com.au/gp/product/B0131LVNW8?*Version*=1&*entries*=0

Brazil http://www.amazon.com.br/gp/product/B0131LVNW8?*Version*=1&*entries*=0

Canada http://www.amazon.ca/gp/product/B0131LVNW8?*Version*=1&*entries*=0

France http://www.amazon.fr/gp/product/B0131LVNW8?*Version*=1&*entries*=0

Germany http://www.amazon.de/gp/product/B0131LVNW8?*Version*=1&*entries*=0

India http://www.amazon.in/gp/product/B0131LVNW8?*Version*=1&*entries*=0

Italy http://www.amazon.it/gp/product/B0131LVNW8?*Version*=1&*entries*=0

Japan http://www.amazon.co.jp/gp/product/B0131LVNW8?*Version*=1&*entries*=0

Mexico http://www.amazon.com.mx/gp/product/B0131LVNW8?*Version*=1&*entries*=0

Netherlands http://www.amazon.nl/gp/product/B0131LVNW8?*Version*=1&*entries*=0

Spain http://www.amazon.es/gp/product/B0131LVNW8?*Version*=1&*entries*=0

USA http://www.amazon.com/gp/product/B0131LVNW8?*Version*=1&*entries*=0

The Moon

Australia http://www.amazon.com.au/gp/product/B00WRPR2S4?*Version*=1&*entries*=0

Brazil http://www.amazon.com.br/gp/product/B00WRPR2S4?*Version*=1&*entries*=0

Canada http://www.amazon.ca/gp/product/B00WRPR2S4?*Version*=1&*entries*=0

France http://www.amazon.fr/gp/product/B00WRPR2S4?*Version*=1&*entries*=0

Germany http://www.amazon.de/gp/product/B00WRPR2S4?*Version*=1&*entries*=0

India http://www.amazon.in/gp/product/B00WRPR2S4?*Version*=1&*entries*=0

Italy http://www.amazon.it/gp/product/B00WRPR2S4?*Version*=1&*entries*=0

Japan http://www.amazon.co.jp/gp/product/B00WRPR2S4?*Version*=1&*entries*=0

Mexico http://www.amazon.com.mx/gp/product/B00WRPR2S4?*Version*=1&*entries*=0

Netherlands http://www.amazon.nl/gp/product/B00WRPR2S4?*Version*=1&*entries*=0

Spain http://www.amazon.es/gp/product/B00WRPR2S4?*Version*=1&*entries*=0

USA http://www.amazon.com/gp/product/B00WRPR2S4?*Version*=1&*entries*=0

The early days of the space race

In my previous post I talked about two significant successes for the Soviet Union in 1957: the first artificial satellite in orbit in October and the first living creature, a dog named Laika, in orbit in November. In December of that year the Americans had a humiliating failure when the Vanguard spacecraft exploded in a massive fireball on the launch pad.

Vanguard TV-3 a few seconds after launch

To boost American prestige and to show the American public that the US wasn’t falling further behind the Soviets, it was important that America get a satellite into orbit as soon as possible. They achieved this when Explorer 1 went into orbit on 1 February 1958.

Explorer 1- Image from NASA

Explorer 1 had a payload of numerous science instruments designed under the direction of James Van Allen (1914-2006), a space scientist at the University of Iowa. It made the discovery that the Earth is surrounded by a belt of electrically charged particles trapped in its magnetic field.  The radiation in these belts is so intense that the readings from the Geiger counter on the spacecraft went off the scale when it passed through them. The belts are invisible to telescopes on Earth which is why they had not been detected previously. Today, in honour of Van Allen, they are known as the Van Allen radiation belts.

The Van Allen radiation belts

Explorer 1, like the Soviet Sputnik 1 and 2 spacecraft, had no solar cells to generate its own electricity. Electrical power came from a non-rechargeable battery. Three and a half months after launch, the battery ran out of charge so the spacecraft couldn’t transmit or receive signals and its instruments stopped working. However, Explorer 1 continued to orbit the Earth as a ‘dead’ satellite for much longer than Sputnik 1 or 2, for reasons which can be seen in the diagram below.

Only Sputnik 1 shown, Sputnik-2 had a similar orbit

As shown above, Explorer 1 was placed in a much higher orbit than Sputnik 1 and 2. At its closest approach it was 358 km above the surface of the Earth and its furthest 2,550 km. The higher a spacecraft’s orbit, the longer it remains in space because the traces of atmosphere which slow it down by friction are much less. Therefore, even though it couldn’t transmit any signals back to Earth, Explorer 1 remained in orbit until March 1970. This was over 12 years after its initial launch, whereas the Sputniks survived in space for around 4 months.

After the success of Explorer 1, the Americans successfully launched 4 other spacecraft into orbit in 1958. However, there were also 18 launch failures, meaning that nearly 80% of American launches in 1958 failed to get into orbit.

Luna 1, 2 and 3

Despite the American successes in 1958, the next big advances in space exploration were all made in 1959 by the Soviet Union. In January 1959 the Soviets launched Luna 1.  This was the first ever spacecraft to reach escape velocity, a speed high enough to enable it to escape from the Earth’s gravity altogether. It flew 6,000 km above the Moon’s surface and during its journey provided direct measurement of the solar wind, a stream of electrically charged particles coming from the Sun. Luna 1 didn’t have a camera, so was unable to send back any pictures of the Moon, but its instruments made the discovery that, unlike the Earth, the Moon has no magnetic field. Interestingly, Luna 1 was actually intended to hit the Moon’s surface but it missed its target due to a navigational error (Zak 2016) so, after passing the Moon, it went into orbit around the Sun, where it remains to this day.

Since 1959 Luna has been orbiting the Sun in an orbit which lies mainly between the Earth and Mars

Luna 2 was launched in September 1959 and this time succeeded in crash landing onto the Moon, becoming the first ever spacecraft to land on another celestial body. This again was a massive propaganda coup for the Soviets.  It even boosted the reputation of the Communist system as a whole, according to some writers of the day: only a successful and thriving country could achieve such great scientific feats.  Although their system couldn’t deliver the same level of material wealth for its citizens as free market capitalism, in 1959 the Soviets were ahead of America in space technology. It would not be until 1964 that America would successfully crash land a spacecraft on the Moon (see notes).

Even more exciting, however, was Luna 3. In October of the same year it became the first ever spacecraft to take pictures of the far side of the Moon, which had never before been seen from Earth and had remained an enigma throughout history.

Luna 3’s images  caused immense excitement around the world. These and subsequent pictures showed that the far side looks very different from the near side. It has a battered, heavily cratered appearance with a relatively small portion of its surface covered by the smooth dark areas (known as seas, or the Latin word maria).

Near and far sides of the Moon

The near and far sides of the Moon (image from NASA)

The greatest leap of all in the early days of space exploration came 18 months later. On 21 April 1961, a Vostok spacecraft containing cosmonaut Yuri Gagarin (1934-1968) launched successfully, performed a single orbit of the Earth, and safely landed 108 minutes later. This was a massive propaganda triumph for the Soviet Union and Gagarin, an air force pilot, became instantly famous throughout the world.

Yuri Gagarin – image from Wikimedia Commons

The American reaction to Gagarin’s flight was swift. A month later President John F Kennedy made the following address to the United States Congress:

“I believe that this nation should commit itself to achieving the goal, before this decade is out, of landing a man on the Moon and returning him safely to the Earth. No single space project in this period will be more impressive to mankind, or more important in the long-range exploration of space; and none will be so difficult or expensive to accomplish.”

Kennedy_May61

President J F Kennedy giving his address on 25 May 1961 – Image from NASA

This was an incredibly ambitious goal, given that in May 1961 America had not yet even placed a man in orbit. Nevertheless, Kennedy was advised that, given sufficient investment by the richest country in the world, a manned landing could be achieved before 1970. There was a good chance that the Soviets simply would not have the money to develop the new spacecraft and technologies required for this incredible leap forward.

So, the American government funded the largest commitment every undertaken by a nation in peacetime. At its peak the programme employed nearly half a million people and its total cost in today’s money was around $180 billion.

All this effort came to successful fruition on July 20 1969, when Neil Armstrong and Buzz Aldrin became the first human beings to land on the Moon. When Armstrong stepped out of the spacecraft he said the immortal words:

That’s one small step for man, one giant leap for mankind.

The Americans had won the space race.

Apollo 11 Astronaut Buzz Aldrin on the Moon – image from NASA

 

Notes

Actually, this is not strictly true.  Ranger 4 crashed on the far side of the Moon in April 1962, thus becoming the first American spacecraft to land on another celestial body. However, due a computer malfunction, it returned no scientific data. The first American probe to land successfully at its planned landing site and send data was Ranger 7 in July 1964.

References

Zak, A (2016) USSR launches the first artificial planet.  Available at: http://www.russianspaceweb.com/luna1.html (Accessed: 30 September 2017).