Throughout human history – and outside of flights of fancy – the Moon has always been thought of as an airless ball of rock, tidally locked to Earth so that it shows the same, almost never-changing face to us in the night sky. But it may not always have been so.
In recent years, our perceptions of the Moon have been changing as a result of a number of studies and missions. In 2009, for example, India’s first lunar mission, Chandrayaan I, produced a detailed chemical and mineralogical map of the lunar surface, revealing the presence of water molecules in the lunar “soil”. In that same year, NASA launched a pair of missions to the Moon, the Lunar Reconnaissance Orbiter (LRO) mission and the Lunar Crater Observation and Sensing Satellite (LCROSS).
LCROSS was a small satellite designed to follow the upper stage of the rocket used to launch it and LRO to the Moon and analyse the plume of debris created by the impact of the upper stage with Cabeus crater in the Moon’s south polar region. The impact came with a kinetic energy equivalent of an explosion created using 2 tons of TNT, and LCROSS recorded strong evidence of water within the resultant impact plume.
For its part, LRO entered lunar orbit to commence a comprehensive campaign of mapping, imaging and probing the Moon’s surface and environment. In doing so, it further confirmed the presence of abundant concentrations of water in the lunar south polar regions. At the same time and LRO has been studying the Moon, an ongoing analysis of the rock samples brought back by the Apollo astronauts has revealed strong evidence for a large amount of water being present in the lunar mantle – possibly as much as is present in Earth’s upper mantle.
These results and findings have given rise to the idea that very early on in the Moon’s history conditions could have been very different to how it is now. In the immediate period following the Moon’s creation (roughly four billion years ago), there are a period when it was very volcanically active (about 3.8-3.5 billion years ago), releasing considerable amounts of superheated volatile gasses, including water vapour, from its interior. This outgassing could have given rise to an atmosphere around the Moon dense enough to support that water vapour condensing out into liquid on the surface which could have conceivably lasted for several million years whilst the atmosphere remained dense enough to support it, before it either (largely) evaporated or retreated underground to eventually freeze.
In their new study, published in July 2018, Dirk Schulze-Makuch, a professor of astrophysics at Washington State University, USA, and Ian A. Crawford, a professor of planetary science and astrobiology at Birkbeck College, University of London, UK, review the evidence for liquid water to have been present on the Moon and examine the potential for it to have been life-bearing. In particular, they note that when all is said and done, if the early conditions on the Moon did give rise to a dense atmosphere and a water-bearing surface, then the conditions there wouldn’t have been that different to those being experienced on Earth when life here was starting up, and would have occurred in the same time frame.
It looks very much like the Moon was habitable at this time. There could have actually been microbes thriving in water pools on the Moon until the surface became dry and dead.
Dirk Schulze-Makuch, co-author of Was There an Early Habitability Window for Earth’s Moon?,
quoted in Astrobiology Magazine
So does that mean life, however transient, got a start on the Moon? Possibly; however, some have suggested rather than giving rise to life directly, the conditions on that early Moon might have been ideal for life from Earth to gain a toe-hold.
As noted, the period when the Moon may have had its dense atmosphere coincided with life starting on Earth in a period referred to as the Late Heavy Bombardment, (4.1 and 3.8 to 3.5 billion years ago). During that time, bacteria such as cyanobacteria were believed to be already present on Earth, even as it was being bombarded by frequent giant meteorite impacts (hence the period’s name). So the suggestion is that this bombardment could have thrown chunks of bacteria-laden rock into space, where they were “swept up” by the Moon, transferring the bacteria to its surface, where it might have taken hold.
It’s unlikely that if it go started, life on the Moon got very far; within a few million years after the end of the Moon’s volcanic period the atmosphere would have been lost, and conditions would have become far too harsh for life to endure. However, in noting this, Crawford and Schulze-Makuch use their study as a call for a more robust study on the potential ancient habitability of the Moon, including a hunt for possible biomarkers.
Such an endeavour would likely be focused on the lunar south polar regions, simply because of the potential abundance of subsurface frozen water there. And as it is, NASA, India and China are already committed to studying the region in great detail. NASA will initially do so from orbit, while the Indian Chandrayaan-2 mission will attempt to place a lander and rover close to the Moon’s south pole in 2019. Also in 2019, China will send its Chang’e 5 mission to the Moon’s north polar regions to gather and return around 2 kg of rock samples for detailed analysis on Earth.
ISS Commercial Flights: Crews Named, But Missions Delayed
NASA has announced the first astronauts who will fly to the International space Station from US soil since the space shuttle ceased operations in 2011. Nine individuals have been selected to fly aboard the first missions of the SpaceX Crew Dragon and the Boeing CST-100 Starliner, and in a harkening back to the earliest days of the US manned space programme which saw the first astronauts selected to fly into space collectively known by the programme to which they had been assigned – the Mercury Seven -, these new selectees are already being dubbed in some quarters the “Commercial Nine” in recognition that they’ll be the first to fly under NASA’s Commercial Crew Programme.
The nine astronauts are:
Boeing CST-100 Starliner Test Flight Crew
- Christopher J. Ferguson (56): a retired US Navy Captain and graduate of both the Navy Fighter Weapons School and the United States Naval Test Pilot School. Flew with NASA three times: as Pilot of shuttle mission STS-115 (Atlantis, 2006), and as Commander of missions STS-126 (Endeavour, 2008), and STS-135 (Atlantis, 2011), the final shuttle mission into space. He resigned from NASA in 2011 to join Boeing, directing Crew and Mission Operations for the CST-100 programme.
- Eric Allen Boe (53): a former Colonel in the US Air Force and an active NASA astronaut. He has previously flown in space twice, as Pilot of shuttle missions STS-126 (alongside of Christopher Ferguson) and STS-133 (Discovery, 2011).
- Nicole Aunapu Mann (41): a Lieutenant Colonel in the U.S. Marine Corps and fighter pilot / test pilot. she is a rookie NASA astronaut, the CST-100 test flight marking her first trip into space.
Boeing CST-100 Starliner Certification Flight Crew
- Sunita Williams (48) a US Navy Captain, a helicopter pilot and graduate of the United States Naval Test Pilot School. She was a Flight Engineer for ISS Expeditions 14 / 15 (2006), Flight Engineer and then Commander during Expeditions 32 / 33 (2012). She is the former record-holder for total space walks by a woman (seven) and most EVA time for a woman (50 hours, 40 minutes)
- Josh Cassada (45): a US Navy Commander and member of NASA Class of 2013. He will be making his first flight into space.
SpaceX Crew Dragon Test Flight Crew
- Douglas Hurley (51): a US Marine Corps Colonel and graduate of the United States Naval Test Pilot School. Has flown in space twice with NASA, occupying the Pilot’s seat aboard STS-127 (Endeavour, 2009) and the final shuttle mission, STS-135, flying alongside Christopher Ferguson.
- Robert Louis Behnken (48): a US Air Force Colonel and graduate of the U.S. Air Force Test Pilot School. He flew as a Mission Specialist aboard the shuttle Endeavour during STS-123 (2008) and STS-130 (2010), both ISS assembly missions during which he accumulated some 19 hours of EVA (space walk) time.
SpaceX Crew Dragon Certification Flight Crew
- Michael Scott Hopkins (48): a Colonel in the US Air Force and a Flight Test Engineer graduate of the U.S. Air Force Test Pilot School. He has flown for 166 days in space as part of the Expedition 37/38 crews (2013-2014) on the ISS, serving as a Flight Engineer.
- Victor Glover (42): a US Navy Commander and graduate of the U.S. Air Force Test Pilot School (and yes, that is “Air Force”, not “Navy”!). He joined NASA as a part of the astronaut intake of 2013, and will be making his first flight into space.
The test flights for both vehicles will be short-term: launch, rendezvous with the ISS, undertake an automated docking, before returned to Earth. The Certification flights will be of longer duration, and intended to fully certify both vehicles for operational use, after which they will commence routine flights to the ISS, carrying both US astronauts and those from international partners involved in the space station. When that will be is currently uncertain. Ahead of the August 3rd, 2018 crew announcement, NASA confirmed that the test flights for both CST-100 and Crew Dragon have been pushed back.
Under the new schedule, SpaceX will fly an uncrewed demonstration of Crew Dragon in November 2018, three months later than previously scheduled, while the crewed test flight will not now occur until April 2019, a delay of four months. The rescheduling is a result of further redesign requirement for the composite over-wrapped pressure vessels (COPVs) used to store helium in the propellant tanks on the Falcon 9, and which much be completed before the vehicle can be certified for human flight.
Boeing’s test programme for the CST-100 has been revised in part as a result of a recent failure during a static-fire test of the vehicle’s abort engines. It means the planned pad abort test will now not take place until later in the summer of 2018, with both the uncrewed and crewed test flights being pushed back until mid-2019.
No dates for the follow-up certification flights for either vehicle were provided with the revised schedule.
There has been speculation on why the initial CST-100 flight has three crew compared when the other flights will only have two. It’s been suggested this is so that, per an agreement signed between NASA and Boeing earlier in 2018, the CST-100’s first flight could be converted into an operational mission should further delays in getting both vehicles to an operational status occur. NASA has thus far declined to comment on this.