I’ve written a lot of late about Saturn’s icy moon, Enceladus. Covered by an icy crust, there is a good chance this distant moon harbours a liquid water ocean beneath that ice. NASA’s Cassini mission has imaged geyser plumes erupting through the ice, and the speculation is that if Enceladus does have an ocean beneath its crust. Now that speculation has been given a sizeable boost.
As a result of a long-term study, on April 13th, 2017 NASA announced the icy plumes of Enceladus contain hydrogen. This is a huge finding; not only does this main the plumes are water vapour, it directly points to a geo-chemical / geo-thermal interaction taking place deep within Enceladus between warm water and rocks which could provide an energy source of microbes.
Current thinking is that life requires three things to get started: water, energy, and the right chemicals. As we know from Earth’s deep oceans, sunlight doesn’t actually enter into the equation; hydrothermal vents provide the energy to support – albeit on a fragile basis – an entire ecosystem from bacteria at the base of the food chain, through tube worms, shrimp, crabs and more. This could well be the case with Enceladus.
As the hydrogen is vented, it is possible that any microbes present in the water of Enceladus could use hydrogen and dissolved carbon dioxide in the water to produce methane in a process called biomethanation (or methanogenesis), one of the foundation processes of life on Earth.
The hydrogen was measured using Cassini’s Ion and Neutral Mass Spectrometer (INMS) instrument. Designed to sample the upper atmosphere of Saturn’s moon Titan, INMS was turned towards Enceladus to follow-up on several discoveries of plumes emanating from the moon’s southern regions dating back as far as 2005.
“This is the closest we’ve come, so far, to identifying a place with some of the ingredients needed for a habitable environment,” Thomas Zurbuchen, associate administrator for NASA’s Science Mission Directorate stated in reference to the report.
Linda Spilker, Cassini project scientist at NASA’s Jet Propulsion Laboratory added, “Confirmation that the chemical energy for life exists within the ocean of a small moon of Saturn is an important milestone in our search for habitable worlds beyond Earth.”
NASA’s Orion / SLS Ambitions Face Delays
In February I wrote about NASA possibly re-scheduling the first flights of their new Space Launch (SLS) rocket system so that the maiden flight could include a crew aboard the Orion Multiple-Purpose Crew Vehicle due to fly as a part of the mission, rather than flying it as an uncrewed mission, and then flying a crew on a second later mission.
Such a move would mean the initial flight of SLS, referred to as Exploration Mission 1 (EM-1), would need to be put back from 2018 to 2019 (at the earliest), to allow time for the Orion vehicle to be correctly outfitted and tested for a crewed mission. However, a new report from NASA indicates that Orion itself may not be ready in time to meet and EM-1 launch in either 2018 or 2019.
The report, published on April 14th, 2017, highlights three significant areas of concern for the programme. The first is that design changes made to Orion’s heat shield now raise technical risks which need to be eliminated. The second is that the Service Module for Orion, which is being developed by the European Space Agency, is facing delays. The third – which is particularly underlined in the report, is that critical software required by both the SLS / SLS systems and need for ground systems at the Kennedy Space Centre in Florida, will not be ready in time.
As a result of the report, NASA is now weighing pushing back the SLS / Orion launch schedule. Nor do the programme’s woes end there; the report also questions NASA’s ability to achieve its longer-term goals with regards to SLS, Orion and Mars, citing the fact that there is no clear roadmap for developing systems (such as a deep-space habitat module, lander / ascent vehicles, etc.) vital for Mars missions.
Without such a roadmap being put in place within the next few years, the report indicates it will be impossible to tell if planned Orion / SLS project expenditure – which is slated to rise to US $23 billion in 2018 and to US $33 billion (including Mars systems expenditure) by 2030 – will be sufficient for the space agency to meet its goals.