Space Sunday: Of Odysseys, rockets, inflatables and exoplanets

Mars Odyssey: 15 years since launch and still going strong

Mars Odyssey: 15 years since launch and still going strong

Fifteen years ago, on April 7th, 2001, NASA launched their Odyssey mission to Mars. Since then, this orbital vehicle, whilst often overlooking in favour of its younger companions, Mars Express from Europe and NASA’s Mars Reconnaissance Orbiter, has done much to revolutionise our understanding of Mars.

Named for 2001: A Space Odyssey, the seminal science-fiction novel by Arthur C. Clarke, Odyssey arrived in orbit around Mars in October 2001. In doing so, not only did it overcome the failures of the 1999 Mars Climate Orbiter and Mars Polar Lander missions, it almost immediately scored its own major success: one suite of instruments found evidence for water ice close to the surface in large areas of Mars – as significant finding which has since gone on to shape much of our thinking about what lies within the Martian crust.

In 2010, Odyssey provided the highest-resolution (at that time) global map of Mars, stitched together from 21,000 images returned by the Thermal Emission Imaging System (THEMIS). Prior to that, in 2008 Odyssey spotted evidence of salt deposits across about 200 places in the south of Mars. NASA considers these areas to be signs of where abundant water used to sit. Scientists theorized the deposits could come from groundwater, which evaporated and left deposits of mineral behind. While in 2007, Odyssey imaged what appeared to be massive cave mouths on the surface of Mars.

THEMIS confirmed the openings – each between 100 to 250 meters (328 to 820 feet) across – were either vertical shafts running into the Martian crust or possibly openings leading to cavernous spaces beneath the surface. Dubbed the “seven Sisters” the openings were discovered on the flank of Arsia Mons, one of the gigantic Tharsis volcanoes, prompting speculation that they might be the collapsed roofs of lava tunnels within the volcano’s slopes.

A 2007 THEMIS image from Mars Odyssey showing entrances to possible Martian caves, dubbed the "seven sisters." Clockwise from upper-left: Dena, Chloe, Wendy, Annie, Abbey, Nikki and Jeanne. Arrows signify direction of solar illumination (I) and direction of North (N) - Credit: GE Cushing, TN Titus, JJ Wynne, USGS, USGS, Northern Arizona University, and PR Christensen of Arizona State University

A 2007 THEMIS image from Mars Odyssey showing entrances to possible Martian caves, dubbed the “seven sisters.” Clockwise from upper-left: Dena, Chloe, Wendy, Annie, Abbey, Nikki and Jeanne. Arrows signify direction of solar illumination (I) and direction of North (N) – Credit: GE Cushing, TN Titus, JJ Wynne, USGS, USGS, Northern Arizona University, and PR Christensen of Arizona State University

The vehicle has also operated in concert with the Mars Reconnaissance Orbiter in support of surface missions, including both the Curiosity and Opportunity rovers. As well as acting as a communications relay for such missions, Odyssey has been able to add context to the rovers’ work by providing thermal and other images which have helped science teams better understand the environments in which the rovers are operating. Nor does it end there. Odyssey has also been a careful observer of the Martian weather.

As each year on Mars lasts around 26 months, Odyssey has observed the planet through more than six Martian years. These observations have revealed some seasonal patterns that repeat each year and other seasonal events, such as large dust storms, which differ significantly from year to year.

A 2001 false colour map of Mars made from data gathered by Odyssey's gamma ray spectrometer reveals the widespread distribution of hydrogen-enriched soil on Mars (in blue), the result of sub-surface ice deposits

A 2001 false colour map of Mars made from data gathered by Odyssey’s gamma ray spectrometer reveals the widespread distribution of hydrogen-enriched soil on Mars (in blue), the result of sub-surface ice deposits

In just this past year, Odyssey’s orbit has put the spacecraft in position to observe Mars in early morning light. Previously, the spacecraft flew over ground that was either in afternoon lighting or pre-dawn darkness. The new orbit enables studies of morning clouds and fogs and comparison of ground temperatures in the morning to temperatures of the same sites in the afternoon and pre-dawn, again helping to increase our understanding of the various atmospheric mechanisms operating on the planet.

With 15 years under its belt, Odyssey continued to work hard around Mars and shows no sign of stopping. So, happy anniversary, Odyssey!

On Land and Sea

Hard on the heels of Blue Origin’s third successful launch and recovery of their sub-orbital New Shephard capsule and propulsion module during a test flight, Elon Musk’s SpaceX has achieved what had been eluding them:  launching a Falcon 9 rocket with a payload bound for the International Space Station and then landing the first stage of the rocket on a platform at sea.

The success comes after four prior attempted to land the first stage of the booster at sea – part of SpaceX’s efforts to develop a semi-reusable system to reduce overall launch costs – all ended with the booster crashing into the floating landing platform, or toppling over post touch-down.

The Falcon 9 1.1 furst stage of CRS-8 stands tall on the the drone ship following its landing on April 8th, 2016

The Falcon 9 1.1 furst stage of CRS-8 stands tall on the drone ship Of Course I Still Love You, following its landing on April 8th, 2016 (credit: SpaceX)

The April 8th launch, officially titled CRS-8, lifted-off from Cape Canaveral Air Force Station, Florida, at 8:53 GMT. After separating from the second stage of the rocket, which carrying the Dragon cargo craft up to orbit, the first stage of the booster performed a series of three burns  to slow it down and boost it back towards the landing platform – referred to as an autonomous drone ship – that was keeping station downrange of the launch site. Eight and a half minutes after the launch, the first stage made a vertical descent over the platform, re-firing its main engines to slow itself as the landing legs deployed from along the side of the rocket’s body, and it eased into a gentle touch-down.

After the landing, crew boarded the platform to weld the rocket’s landing pads to the deck as a precaution against it toppling over while the platform was being towed back to port. Current plans call for the platform to undergo examination and testing at Kennedy Space Centre to ensure no structural damage occurred during the landing, before it is refurbished for a further at-sea landing, possibly in June 2016. The Falcon booster stage will  also undergo post-flight examination prior to being refurbished for a future launch.

inflatables in Space

Part of the payload carried up to the ISS by the Dragon vehicle launched during CRS-8 is an inflatable module  referred to as the BEAM, the Bigelow Expandable Activity Module, built by Bigelow Aerospace.

Carried in the unpressurised cargo area of the Dragon, which reached the ISS on Sunday, April 10th, where it was successfully docked with the assistance of the station’s robot arm, BEAM is a test module designed to investigate the use of “inflatable” structures in space. In particular, the room-sized module, once deployed and attached to the space station will be used to investigate how well it protects against solar radiation, space debris and contamination.

The Bigelow Expandable Activity Module, delivered to the ISS on Sunday, April 10th by SpaceX CRS-8

The Bigelow Expandable Activity Module, delivered to the ISS on Sunday, April 10th by SpaceX CRS-8 (credit: Bigelow Aerospace)

If successful, BEAM could pave the way for much larger inflatable structures, which could be used as orbital facilities and to provide habitation units for things like bases on the lunar surface or on Mars or even as the habitat modules on interplanetary missions.   They have the advantage of being fair more lightweight than conventional structures, and can obviously be packed into a smaller space during launch, making them far more cost-effective.

BEAM is due to be deployed some time between the 15th and 18th of April, and will provide 16.3 cubic metres (565 cu ft) of space, which will be equipped with monitoring equipment during the 12-18 months the unit will be tested. It will not be used as a part of the space station’s habitable areas, but a crew member will enter the module three to four times per year to collect deployment dynamics sensor data, perform microbial surface sampling, conduct periodic change-out of the radiation area monitors, and inspect the general condition of the module.

Bigelow aerospace is already working on a much bigger inflatable module - the BA330, two of which might be used ro develop what the company calls "Space Station Alpha", which might fly some time after both SpaceX and Boeing commence operations with their Commercial Crew vehicles, the Dragon V2 and Starliner

Bigelow aerospace is already working on a much bigger inflatable module – the BA330, two of which might be used ro develop what the company calls “Space Station Alpha”, which might fly some time after both SpaceX and Boeing commence operations with their Commercial Crew vehicles, the Dragon V2 and CST-100 Starliner (credit: Bigelow Aerospace)

Bigelow Aerospace is already working on a much bigger inflatable module – the BA330 – two of which might be used to form what the company calls “Space Station Alpha”. Already under development, with a potential launch date of late 2018 or 2019. If flown, the station would be serviced by both the SpaceX Dragon 2 vehicle and Boeing’s CST-100 Starliner craft, which are both due to start flying crews to and from the International Space Station around the same time.

Kepler Woes

NASA space-based “planet hunter”, the Kepler Space observatory, unexpectedly entered what is called Emergency Mode in early April, prompting concerns over it’s future.

Launched in 2009, the observatory is in a heliocentric orbit, currently trailing Earth by around 121 million kilometres (75 million miles). From that position it has been surveying the stars around us, hunting for planets which may be orbiting them by using a photometer to measure the brightness of the stars and detect any periodic dimming caused by planetary bodies orbiting the stars passing between them and the observatory.

Artist's impression of the Kepler Space Telescope, which orbits the Sun some 120 million km behind the Earth (image: NASA Ames)

Artist’s impression of the Kepler Space Telescope, which orbits the Sun some 120 million km behind the Earth (image: NASA Ames)

Now into its seventh year of operation, and well into an “extended mission” phase, Kepler has been remarkably successful, discovering over 4,000 potential exoplanets in that time, with over 1,000 subsequently confirmed, some of them “Earth like” in size and density, if not always in the “Goldilocks zone” around their parent stars where life might have been able to get started on them.

The mission has not been without some upsets.  Core to its ability to make accurate observations, Kepler must be an exceptionally stable platform. To achieve this, it used a set of four reaction wheels, with only three being required for accurate positioning.  However, in July 2012, one of the wheels failed, followed in May 2013 by the failure of a second, effectively ending the observatory’s primary mission.

However, rather than lose the mission entirely, engineers worked out a way for Kepler to use both its remaining fully functional reaction wheels and the pressure of the solar wind to initiate a new, “extended” mission, referred to as K2. During this phase of the mission, Kepler has not only been able to continue to seek out strange, new worlds beyond our solar system, but has also been imaging supernovae.

Earth (l) and Kepler (r) sun with there respective stars, as each might look from orbit

Earth (l) and Kepler 425b (r), one of the Earth-like worlds located by the Kepler observatory sun with their respective stars, as each might look from orbit (credit: NASA)

The latest situation with the observatory currently has the mission team mystified. Communications with the platform take place at scheduled times which can be days apart. On April 4th, during one such communications period, Kepler was fine; but at the next period, on April 7th, Kepler reported it was in Emergency Mode (EM).

This means the platform is in its lowest operational mode; all science observations have halted and it is essentially asking for help. However, EM is also very fuel-intensive, as the platform is more reliant on its reaction motors keep its communications antenna aligned with Earth. It’s therefore very important for mission staff to determine what has happened and how to correct it  before Kepler exhausts its fuel reserves.

Currently, a mission emergency has been declared, prioritising communications with the platform through NASA’s deep space network. Even so, diagnosing the problem could take time – it takes 13 minutes for a communications signal to reach Kepler, and a further 13 minutes to get a response.

Prior to the issue, Kepler has been running at peak efficiency – better than it had through most of its mission, in fact. This, and the on-board reserves of fuel had left the mission team confident Kepler could continue gathering data on potential exoplanets through until late 2018.

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