NASA’s Exploration Mission 1 (EM1) and Who Might Launch it.

The Vice President of the US announced that the administration wants the US to return astronauts to the Moon by 2024. For this to happen there needs to be a way of getting them there and the SLS will probably not be ready.

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A week ago we made some assertions about how SpaceX or ULA and Nasa might cooperate on getting back to the Moon and the announcements coming out of the US this week seem to point in that direction as well. The Vice President of the US announced that the administration wants the US to return astronauts to the Moon by 2024. For this to happen there needs to be a way of getting them there and a year ago it looked like the Space Launch System (SLS) was the only option. The world watched with interest as SpaceX entered the heavy lift market with the first launch of the Falcon Heavy, about a year ago, and just last week Jim Bridenstine announced that NASA would be open to looking at commercial options for the Exploration Mission 1 to meet the timeline of launching an Orion Spacecraft by June next year.

The mission profile for a commercially launched Orion would be along the lines of the spacecraft being launched into Low Earth Orbit followed by another rocket launching and docking with the orbiting spacecraft to provide another module, not dissimilar to SpaceX’s profile that they were going to use for the BFR mission to go to Mars that Elon Musk presented in late 2017. To do this is not easy, first there needs to be a way of docking the spacecraft to the second component, this has to be fabricated and tested, then certified for flight. There’s two viable contenders for launching the Orion Spacecraft, one is ULA’s Delta IV Heavy and the other is SpaceX’s Falcon Heavy. The safe bet is the Delta IV Heavy as it’s been launched many times without any problems while the SpaceX option has only had one launch so far (one is due in April so their stats might double shortly!).

Delta IV Heavy launching the Exploration Flight Test 1 (Credit: NASA via Wikipedia)

So the path to a commercially supported launch of astronauts to the Moon would look something like this. First the Orion would have to be fitted to the rocket. This would require building and testing of the airframe to make sure it would fly properly. This is not really a problem for ULA as an early version of the Orion Spacecraft flew on a Delta IV Heavy back in 2014 in the Exploration Flight Test 1. The launch abort test was originally scheduled for 2017 but the current plan is for that to occur in June this year. With the announcement of the accelerated timeline for launching astronauts to the Moon it is very likely the launch abort system test will go ahead shortly so the spacecraft will be certified for use.

Orion Spacecraft atop the Delta IV Heavy (Credit: NASA/ULA via Wikipedia)

The EM1 mission is supposed to be launched in June 2020 but it is clear that unless something miraculous happens, then the SLS will not be ready by then – hence the NASA announcement about leaving the door open for commercial options. This means that the most likely configuration for the EM1 will be a Delta IV Heavy rocket launching the Orion spacecraft. The EM1 mission is supposed to send the spacecraft around the Moon which is quite an ambitious goal if the rocket is going to be changed. The main challenge is that the mission would need to involve two launches, one with the spacecraft and one with the interim cryogenic propulsion stage – which is the basically the rocket motor to propel the Orion spacecraft to the Moon. The two parts will then have to join together in Low Earth Orbit. This is the tricky bit because both components were supposed to launch in one rocket, the SLS, so there would have been no need to perform a complex manoeuvre.

Artists impression of the Orion and Interim Cryogenic Propulsion Stage (Credit: NASA via Wikipedia)

The cost of Delta IV Heavy launch is about USD$350 million per launch, so for two of them the EM1 mission might be well in excess of USD$700 million. The other option, which seems a little less likely, is using a Falcon Heavy to launch the two components. From a cost perspective, for the launch, it could be as little as USD$180 million to get both components into orbit which is considerably cheaper than the Delta IV Heavy option. The main problem with this possibility is the Falcon Heavy is not yet a proven system and it is up against the already flight tested Orion having been launched on the Delta IV Heavy. Notwithstanding this, SpaceX has a habit of doing things quickly so it is still a viable option. The next few months will be very interesting to see how the EM1 mission profile develops and just what rocket will be used.