Many planetary scientists believe that Europe may be our best chance of finding evidence of alien life in our own backyard. Although it is a large backyard, and the planned Europa Clipper mission needs a powerful rocket to reach the Jovian moon. Congress previously demanded that this mission be launched on the massively delayed Space Launch System (SLS), but the latest NASA budget has released the agency’s hands.
Europa Clipper is an ambitious long-term robot mission aimed at studying Europe up close using several orbital flybys. NASA hopes to launch the spacecraft in 2024 and send it on a six-year journey to Jupiter. Once there, the spacecraft will spend at least four years orbiting Europe to scan its entire surface. The probe will also have tools to characterize the presumed sea below the surface beneath the cracked ice sheet.
The ongoing problems in getting the SLS rocket complete have added uncertainty to the Europa Clipper timeline, and NASA was not allowed to explore alternatives. This restriction is thanks to congressional voting – a former U.S. representative from Texas pushed funding for the Clipper mission, and he received Senate support from Republican Richard Shelby by including the SLS mandate. Shelby’s home state of Alabama has a large number of aviation contractors who stood to benefit from SLS.
NASA has called on Congress to reconsider this mandate, and it looks like the announcement has finally come through. In the recently approved budget, the NASA section includes a change to the SLS mandate – it’s not gone, but NASA has much more leeway to explore alternative ways to get the Europa Clipper into space. While NASA will still need to use the SLS if it is ready in 2024, the agency could instead use something like the SpaceX Falcon Heavy if the SLS still runs backwards.
The Space Launch System was pushed by Congress as an alternative to the Constellation program, which the Obama administration canceled in 2009. In return, the administration got the Commercial Crew program, which recently managed to send astronauts into space. SLS is destined to be the most powerful rocket in the world when completed, but it is an expensive disposable vehicle with an expected launch cost of more than $ 2 billion. A Falcon Heavy launch would save NASA approx. 1.5 billion $. Although the SLS has enough power for a direct flight to Jupiter, while the Falcon Heavy launch will involve some planetary slingshot maneuvers.
It is unclear which direction NASA will go – SLS is currently expected to have its first test flight in 2021 with a crew mission in 2023. If that holds, NASA can still use SLS for the Europa Clipper. Fortunately, the Agency will not be hampered in the event of further delays.