While opinions may be in a state of flux over what constitutes a dwarf planet – the recent discoveries around Pluto’s interaction with the solar wind once again highlighting the debate, the fact remains that there are a fair few to be found in the solar system, with the largest five, as traditionally listed in descending order of volume, being: Pluto, Eris, Haumea, Makemake and … 2007 OR10.
These worlds are so small and so far away – in relative terms – that gathering data on them without actually paying them a visit, as we’ve done with Pluto, isn’t easy. In the case of 2007 OR10, this lack of information means it has been left without a name, only a designation related to its year of discovery.
However, all this might now be changing after data gathered by the Kepler observatory (about which I’ve written in recent Space Sunday reports) has helped reveal the dwarf planet – which orbits the Sun once every 547.5 years – is actually the third largest such body beyond the orbit of Neptune, sitting behind Pluto and Eris, and thus it could be a lot more interesting than first thought.
Up until now, it had been thought 2007 OR10 was about 1280 km (795 mi) in diameter. However, such is the sensitivity of Kepler’s instruments in measuring light variations whilst seeking extra-solar planets orbiting nearby stars, that the observatory has been able to precisely measure variations in the brightness of this unusually dark little world. These measurements, combined with data obtained from the Herschel Space Observatory, suggest that 2007 OR10 is around 1535 km (955 mi) in diameter, or about 255 km (160 mi) larger than previously thought.
The upshot of this is the dwarf planet is liable to be a far more interesting place than previously thought, potentially covered in volatile ices of methane, carbon monoxide and nitrogen, and may even be somewhat active as a result of its interaction with the solar wind. It also means that it is really overdue for a decent name.
According to convention, the honour of naming it goes to the planet’s discoverers, in this case Meg Schwamb, Mike Brown and David Rabinowitz. They discovered it in 2007 during a search for distant bodies in the Solar System. In fact, Mike Brown has already suggested a name: Snow White, in recognition of the planet’s ice surface composition.
However, this hasn’t stopped suggestions rolling in from the general public – up to and including, “Dwarfy McDwarfface”, in recognition of the recent public voting on the name for the UK’s new polar research ship.
I have to admit that – and indifference to Mike Brown’s suggestion, which doesn’t take into account 2007 OR10’s likely rusty complexion – my personal favourite suggestion has to be that from Greenwood Space Travel Supply Co (shown above right), which puts forward a very strong case for the name of this little world. I’m also wearing my Dwarf Planet Pride Day badge with … pride!
Two Years of Weather Reporting on Mars
NASA’s Curiosity rover has completed its second year on Mars – its second Martian year, that is; August 2016 will actually mark the end of its fourth Earth year of operations in Gale Crater. This milestone is important, as it means that the rover has been able to accumulate data on two full cycles of Martian seasons and weather.
Gathering data over so long a period helps distinguish seasonal effects from sporadic events. For example, a large spike in methane in the local atmosphere during the first southern-hemisphere autumn in Gale Crater was not repeated the second autumn; it was an episodic release, albeit still unexplained. However, the rover’s measurements do suggest that much subtler changes in the background methane concentration may follow a seasonal pattern; while measurements of temperature, pressure, ultraviolet light reaching the surface and the scant water vapour in the air at Gale Crater show strong, repeated seasonal changes.
Monitoring the modern atmosphere, weather and climate fulfils a MSL mission goal, supplementing the better-known investigations of conditions billions of years ago. Back then, Gale Crater had lakes and groundwater that could have been good habitats for microbes, if Mars has ever had any. Today, though dry and much less hospitable, environmental factors are still dynamic.
Curiosity’s Rover Environmental Monitoring Station (REMS), supplied by Spain’s Centro de Astrobiología, has measured air temperatures from 15.9o C (60.5o F) on a summer afternoon, to -100o C (-148o F) on a winter night.
“Curiosity’s weather station has made measurements nearly every hour of every day, more than 34 million so far,” said Curiosity Project Scientist Ashwin Vasavada. “The duration is important, because it’s the second time through the seasons that lets us see repeated patterns.”
The similar tilts of Earth and Mars give both planets a yearly rhythm of seasons. But some differences are great, such as in comparisons between day and night temperatures. Even during the time of the Martian year when temperatures at Gale Crater rise above freezing during the day, they plummet overnight to below -90o C (-130o F), due to the thin atmosphere. Also, the more elliptical orbit of Mars, compared to Earth, exaggerates the southern-hemisphere seasons, making them dominant even at Gale Crater’s near-equatorial location.
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Curiosity’s air-pressure measurements confirm a strong seasonal trend previously seen by other missions. There are large changes due to the capture and release of carbon dioxide by the seasonal polar caps. Most of the Martian atmosphere is carbon dioxide. During each pole’s winter, millions of tonnes of this gas freeze solid, only to be released again in spring, prompting very un-Earthlike seasonal variations of about 25% in atmospheric pressure.
Other seasonal patterns measured by Curiosity and repeated in the rover’s second Martian year are that the local atmosphere is clear in winter, dustier in spring and summer, and windy in autumn. Visibility in Gale Crater is as low as 30 km (20 mi) in summer, and as high as 130 km (80 mi) in winter.
While continuing to study the modern local environment, Curiosity is investigating geological layers of lower Mount Sharp, inside Gale Crater, to increase understanding of ancient changes in environmental conditions. I recently wrote about the rover’s examination of “Naukluft Plateau”. NASA has produced an interactive video allowing you to see the plateau from Curiosity’s perspective.
Boeing Delay CST-100 Starliner Flight Programme
US Aerospace company Boeing has announced it is pushing back the flight programme for its CST-100 Starliner “space taxi”, designed to fly crews to and from the International Space Station from US soil.
Boeing, who are providing the capability alongside of SpaceX, had originally hoped they would be in a position to make their first crewed flight to the ISS in late 2017.
However, as the first prototype vehicle, referred to as the Structural Test Article (STA), has been coming together at Boeing’s Commercial Crew and Cargo Processing Facility (C3PF), located in NASA’s Kennedy Space Centre (KSC), Florida, Boeing have recognised mass and aerodynamic issues which must be addressed.
As a result, the planned Launch Pad Abort Test has been rescheduled from June 2017 to October 2017, and the first uncrewed orbital test flight pushed from October 2017 to December 2017.
This means the first crewed test flight, which had been targeted at December 2017, and would see a 2-person crew from NASA and Boeing dock a CST-100 with the ISS, will not now take place until at least February 2018.
The CST-100 Starliner is part of NASA’s Commercial Crew Program (CCP), which was put together with the intention of ending America’s reliance on Russia for crewed launch capabilities, whilst also freeing the US Space Agency to focus on taking humans further into the solar system – such as through a return to the Moon and crewed missions to Mars.
It had been hoped that the programme might have seen the first flight of commercial vehicles handling crew missions to / from the ISS commence around late 2015 / early 2016. However, since 2011, it has been repeatedly hamstrung by budget cuts imposed by Republican-controlled Congress. While the delays with the CST-100 aren’t directly attributable to existing budget cuts, it is possible they may result in further political hostility towards the programme.
In the meantime, Boeing’s STA is nearing completion, and will be used for a period of critical stress testing designed to verify the capabilities and worthiness of the spacecraft under the types of loads and stresses it will face during a typical launch and flight envelope.
NASA has not formally announced when the first crewed launch to the ISS will be made, or whether Boeing or SpaceX (who will be using their new multi-purpose Dragon 2 vehicle), will be selected for that flight. That decision will be based purely on which company satisfactorily completes all of the required pre-flight tests and uncrewed flight tests to the space agency’s satisfaction.
Is the X-37B An Orbital “Spy Plane”?
A year ago, I wrote about the 4th flight of the US Air Force X-37B “mini shuttle”, an uncrewed vehicle referred to by the USAF as an “orbital test vehicle”. The craft, which is launched atop an Atlas V booster, was taken over by the USAF from a previous project undertaken by NASA. Since then, it has undertaken three clandestine flights in 2010/11, 2011 and 2012/14, leading to speculation it is part of a space weapons testing system.
The May 2015 launch, however, seemed to scotch these rumours, with the USAF revealing the vehicle was carrying aloft an advanced Hall thruster propulsion system (a sort of ion propulsion system used in things like communications satellites) and a NASA materials investigation project. However, with almost a year in space, people are again beginning to question the vehicle’s real purpose. While 365 days falls short of the 469 day the X-37B spent in orbit during its second flight, and fades into insignificance compared to the 675 days of its third mission, the time span doesn’t seem to be consistent with testing a propulsion system that’s already in use or with materials investigations.
Speculation is therefore again growing that the X-37B might actually be an orbital “spy plane”, testing (and possibly using) new surveillance and reconnaissance technologies, and investigating how they stand up to radiation and other orbital hazards over long-duration missions. It’s not the first time the theory has been put forward; much the same was said at the time of the vehicle’s third flight.
The USAF remains, naturally enough, silent on the matter. However, military and space analysts who have previously refuted ideas that the vehicle might be a potential platform for espionage have acknowledged that while its use to spy on the space activities of other nations – as the USAF was accused of doing with China’s Tiangong-1 space station module – are pretty far-fetched due to the complexities of orbital mechanics, have suggested the use of the vehicle for observing what might be going on on the ground could be plausible.
Transit of Mercury
If you missed the transit of Mercury on Monday, May 9th, when the tiny planet passed between the Earth and the Sun, revealing itself against the Sun’s disk, you can catch up with it through the video below which compresses the entire 7.5 hour event into less than a minute and a half, as seen from NASA’s Solar Dynamics Observatory (SDO), occupying a Geosynchronous orbit above the Earth.