NASA’s Cassini mission has completed the first of its final 22 “dives” through the gap between Saturn its ring system. In the process, the craft came to its closest past so far over the planet’s cloud tops.
As I noted in my previous Space Sunday update, after 20 years in service and with manoeuvring fuel running out, the mission is set to end on September 15th, 2017, when the veteran spacecraft will enter the upper reaches of Saturn’s atmosphere and burn up, preventing any risk of the vehicle colliding with one of Saturn’s moons and risk contaminating it with the radiation from its plutonium power cells.
This first pass between planet and rings was a complete dive into the unknown – so much so, that the spacecraft was out of contact for 20 hours during the critical part of the pass. This was because prior to making the pass, the vehicle had to be oriented so that its 4-metre (13 ft) diameter communications dish was facing away from Earth and into the direction of flight, so it could act as a shield to prevent any dust particles within gap impacting more sensitive parts of the vehicle.
NASA’s Deep Space Communications network lost contact with the vehicle at 09:00 UT, on April 26th, as Cassini cross Saturn’s ring plane. The signal was successfully re-acquired at 06:56 UT on April 27th, after the vehicle had cleared the gap and could re-orient itself and point its communications dish back towards Earth. The transfer of data gathered during the pass commenced a few minutes later.
“No spacecraft has ever been this close to Saturn before. We could only rely on predictions, based on our experience with Saturn’s other rings, of what we thought this gap between the rings and Saturn would be like,” said Cassini Project Manager Earl Maize at NASA’s Jet Propulsion Laboratory, California, as the data from the spacecraft started flowing. “I am delighted to report that Cassini shot through the gap just as we planned and has come out the other side in excellent shape.”
The gap between the rings and the top of Saturn’s atmosphere is about 2,000 km (1500 mi) wide, and Cassini came within 3,000 km (1900 mi) of Saturn’s cloud tops, in an area where there was a risk of smoke particle sized motes of dust being encountered. Small as they might be, the fact that the probe was travelling at some 124,000 km/h (77,000 mph) relative to Saturn meant that any dust striking an unprotected part of the vehicle could have been catastrophic, hence using the communications antenna (which could suffer some damage without serve loss of capability) as a shield.
“In the grandest tradition of exploration, NASA’s Cassini spacecraft has once again blazed a trail, showing us new wonders and demonstrating where our curiosity can take us if we dare,” said Jim Green, director of the Planetary Science Division at NASA Headquarters.
The data from Cassini is already being analysed and revealing more about Saturn and it’s atmosphere, but it has been the images that were released following the pass which have stunned observers on Social media – although some needed to have their perspective adjusted as the first of the raw images appeared.
“Hey, it’s a GIF of something you think’s gonna be cool, but it’s Cassini proving it’s no better at camera s*** than somebody getting shot at,” one commentator chose to Tweet. This prompted a quick response from fellow space enthusiast, Jason Major (whose images are used in this article); “Cute. Now realise Cassini is taking these pics w/a camera built in 1996 while travelling 65,000 mph where sunlight is 100x dimmer than here.”
NASA Confirms Orion / SLS EM-1 Delay
NASA has now confirmed the first launch of the Space Launch System (SLS), NASA’s new super rocket, and the Orion Multi-Purpose Crewed Vehicle will be delayed. Expected to take place in November 2018, it will now not occur until 2019 at the earliest.
The decision comes as a result of a number of factors. As I recently reported, software critical to the mission is lagging in development, as is the European built Service Module. The latter is designed to provide the Orion capsule with propulsion, power and consumables. The first Service Module was due to be delivered to NASA in January 2017, but will no not arrive before August 2017. and will then require at least 12 months of integration and testing, putting a November 2018 launch in severe doubt. A third factor playing a role in the delay is the February tornado which swept though the New Orleans area, damaging the Michoud Assembly Facility where much of the SLS core stage is being constructed.
Earlier in 2017, in response to a White House request, NASA had been weighing the option of delaying the first SLS / Orion launch in order to make it a crewed mission – something not currently on the cards until at least 2021 with Exploration Mission 2. The announced delay to EM-1 has no bearing on whether or not it might proceed as a crewed mission, as there is an entirely separate list of technical challenges around this which need to be understood in full before any decision can be made.
Yes, We Don’t Have a Space Suit
One of the items potentially standing against a crewed first mission for Orion / SLS – indeed, which could result in NASA delaying crewed launches aboard the system somewhat later than the proposed 2021 EM-2 crewed flight – is that NASA doesn’t actually have a spacesuit suitable for use with the vehicle.
US space operations currently depend on the shuttle-era Extravehicular Mobility Units (EMUs), four of which are in constant use aboard the International Space Station, and the remaining seven are Earthbound. These suits are already beyond their planned 15-year lifespan and are unsuitable for operation within Orion or with any of NASA’s broader ambitions for human space exploration activities, so new suits are required. Indeed, they’ve been in development since 2007 – but are nowhere near ready for delivery, despite the US $200 million spent on them in that time.
The first suit considered to replace the EMU was the Constellation Space Suit System (CSSS), a modular approach to space suit design initiated as part of the overall Constellation programme initiated in 2005 and cancelled due to cost overruns and other factors in 2010 (with the exception of the Orion vehicle itself), and replaced by Orion / SLS.
However, despite the programme cancellation, NASA continued to pay Oceaneering, the prime contractor for the CSSS to the tune of US $80.8 million between 2011 and 2016, bringing the total expenditure on CSSS to over US $135 million, despite the fact it will likely never be used. At the same time, NASA has invested a further US $51.6 million in its own space suit development programme, the Advanced Space Suit Project (ASSP).
If this sounds confused, it is – at least in part. While NASA does have grand ambitions for human space endeavours which involve deep space / cislunar space operations, a return to the Moon, missions to Mars, etc., it does actually have a coherent strategy for achieving these goals. As these various environments – space, the surface of the Moon and the surface of Mars actually all require different capabilities from a spacesuit, which involve different challenges / requirements in spacesuit design.
The CSSS, for example, was to come in two “Configuration Modes”, with elements of the suit being interchangeable between the two modes. The first of these, called “Configuration One” was what might be called a “soft” suit, designed for mission launches and EVA activities in space, and somewhat resembles the current EMU. The “Configuration Two” version of the suit would have used a “hard shell” with integrated backpack (which would open in a similar manner to Russian space suits to allow astronauts ease of entry / egress), specifically designed for operations on the lunar surface.
Because NASA doesn’t have a clear strategy for achieving its space ambitions, those involved in the spacesuit development programmes have been left to try to find their own way. Hence the disparate expenditure and potential duplication. Criticised soundly for the situation by its own Office of Inspector General (OIG), the agency has sought to justify the duplication of efforts between ASSP and CSSS by saying they have provided important insights into the overall development of space suits. It has also agreed to re-focus its approach to spacesuit development between now and September 2017.
Which brings us to the Orion situation, as there is actually a third suit development programme in the mix. This is the Orion Crew Survival System (OCSS), designed to keep crews aboard the Orion vehicle safe during various aspects of a mission.
As a result of the muddled approach to suit development, the OCSS has at times been short of funds, leading to delays in its development. So much so that the first flight-ready versions of the suit are unlikely to be available for testing until May 2021, just over five months ahead of the current planned launch period of the Orion / SLS EM-2 mission – and even then, the suit is expected to undergo extensive pre-flight testing aboard the ISS.
Given all of this, it would seem unlikely the OCSS could be ready in time for a crew to fly aboard the EM-1 mission in 2019, unless NASA is able to adopt an alternative, such as the Boeing Starliner suit.
China and Europe to Print Moon Base in the 2020s?
China has made no secret of its space ambitions. Right now it is testing on-orbit rendezvous and refuelling of orbital facilities using the automated Tianzhou-1 cargo vehicle and (currently uncrewed) Tiangong-2 space laboratory, becoming only the third nation after Russia and America to do so. It has also indicated that in 2018 it will start constructing a permanently manned space station in Earth orbit, and intends to fly further automated and then crewed missions to the Moon and Mars.
In respect of those lunar ambitions, it now seems as if China is about to enter into a partnership with the European Space Agency (ESA) to establish the first “lunar village” in the 2020s using, among other technologies, a form of 3D printing to assist in construction of the facilities.
The China National Space Administration (CNSA) and ESA have been in general discussion about potential cooperation in lunar activities for some time. But on April 26th, Tian Yulong, the Secretary General of the Chinese space agency indicated CNSA and ESA were ready to start work on development of a lunar base. When asked about the statement, ESA’s head of media relations, Pal A. Hvistendahl confirmed the potential for cooperation.
Yulong and Hvistendahl indicated that this base would aid in the development of lunar mining, space tourism, and facilitate missions deeper into space – particularly to Mars. It would also build upon recent accomplishments by both agencies, which have successfully deployed robotic orbiters and landers to the Moon in the past few decades.
While no details of this proposed village have been released, it seems likely it will build on the vision expressed by ESA director Jan Woerner to create a “low-cost” international lunar base as a successor to the International Space Station. In particular, it will utilise “additive manufacture” (that’s 3D printing to you and me).
In 2013, ESA teamed with architects Foster+Partners to test the feasibility of using lunar soil (known as regolith) in a process that would effectively “print” a protective layer over the facilities of a lunar base to provide protection from harmful radiation and micrometeorites. Initially used for a single dome delivered to the lunar surface via automated means, the technique could be used with multiple domes to create a (relatively) low-cost lunar village suitable for a range of activities.
China has so far been denied a place at the table of cooperative ventures in space, largely as a result of US legislation and ostensibly because of CNSA’s military ties. However, were such a cooperative venture between China and ESA to go ahead, some see it as a potential spur towards greater cooperation involving NASA and Russia’s Rovkosmos.