EM-1 could become Apollo 8 for the 21st century
NASA is taking a hard look at having crew fly on the first integrated mission of the agency’s Space Launch System (SLS) super-heavy-lift rocket and Orion spacecraft. At present, NASA is only undertaking a feasibility study, reviewing what risks would be incurred, what needs to be added to allow for this happen, and what potential benefits could be had.
Acting NASA Administrator Robert Lightfoot announced on Feb. 15, 2017, that he was ordering a study on the feasibility of adding crew. It was to be lead by William Gerstenmaier, NASA’s Associate Administrator for Human Exploration System Directorate.
In a Feb. 24, 2017, teleconference, Gerstenmaier, along with Deputy Associate Administrator for Exploration Systems Development William Hill, addressed a number of questions and concerns about the potential crew addition stressing that this is only a feasibility study and the baseline Exploration Mission-1 (EM-1) flight is still moving forward as originally planned.
“When we get done with this, we won’t come out with a hard recommendation one way or the other,” Gerstenmaier said. “We’re going to talk about essentially the advantages and the disadvantages of adding crew to EM-1.”
According to Gerstenmaier, the White House asked NASA to look into the option, adding that there has been no guarantee of more money for a possible crewed flight.
The baseline schedule currently calls for a Block 1 SLS to send an uncrewed Orion spacecraft into a distant retrograde lunar orbit in late 2018 – EM-1. The flight would last about 20 days. Then, in August 2021, the EM-2 flight would see a Block 1B SLS, with a new Exploration Upper Stage (EUS), send a piloted Orion on a shorter 8-day free return trajectory around the Moon.
The mission being studied would send two crew members in Orion on a similar trajectory that EM-2 would have performed. It would involve a day in high-Earth orbit to verify critical systems, such as life support, before performing a trans-lunar, free return trajectory burn using the Interim Cryogenic Propulsion Stage (ICPS) – a modified Delta IV upper stage.
“We’ll get a chance to test systems in a very rigorous way with [a] crew on board,” Gerstenmaier said. “Some of the life support systems will get to see crew interaction with the vehicle, which helps us get to an overall readiness standpoint.”
The study will look into what systems will need to be added to EM-1 which were not already included, such as life support, crew displays, and an active Launch Abort System (LAS) – none of which are planned to fly on the baseline mission. Additionally, it will look into what hardware may have to be changed as well as additional tests that will need to be done.
For example, the ICPS, while it is powerful enough to perform the mission requirements, is not human rated. The study will have to look at what will need to be changed to alleviate some risk. This might also include adding more debris protection for the highly elliptical orbit.
“We think we can set up a profile that limits crew risk exposure, so if something doesn’t go right with the upper stage, then we can abort out of that and send the crew home safely,” Gerstenmaier said.
Gerstenmaier said that they might lose the mission, but they can still protect the crew. He has asked the team performing the study to look how feasible that is.
“It is going to be a risk balance,” Hill said. “We’ll take a look at the risk versus the benefits. If we can fly the EM-2 profile on EM-1, that opens up EM-2 to do more because we have at least some experience and we can do more with that as opposed to the profile we earlier anticipated with flying crew on EM-2.”
Additionally, Gerstenmaier said that they are looking at ways to reduce the risks associated with this prospective mission. One way would be to accelerate the Ascent Abort-2 test to early 2019.
Other ways the SLS and Orion team has already been attempting to buy-down risk include testing hardware on board the International Space Station. There is a carbon dioxide removal system on the outpost that has been running for over 2,000 hours so far. Later, a waste management system will be sent to the orbiting laboratory for tests as well.
“We recognize this will be an increased risk, and we take that increased risk, and we take it against the benefits that we gain by doing this, and we say, ‘hey, is that something that’s worthwhile for us to go do?’,” Gerstenmaier said. “Then we have an agency-wide discussion on whether this is the appropriate risk for us to take.”
Gerstenmaier said that one of the main questions the study will be looking at is what the agency would gain by a crewed EM-1 flight. Does it significantly advance its overall capability to take people to the Moon regularly? He also said there are astronauts on the team that will be contributing directly to this discussion.
Knowing that adding crew to EM-1 will cause a delay from the current late 2018 launch date, Gerstenmaier said he arbitrarily limited the study to changes that would allow for a mission to launch no later than late 2019.
“If it goes much beyond 2019, then basically the plan we’ve got today with EM-2 with [a] crew is probably as good of [a] plan as we have and there’s not a tremendous advantage [to add crew to EM-1],” Gerstenmaier said.
There was also an option of accelerating EM-2 instead of crewing EM-1, but that was ruled out because of the extensive changes to ground systems that would be needed. There simply isn’t enough time between launching a 322-foot (98-meter) tall Block 1 SLS and the 364-foot (111-meter) tall Block 1B to change out the hardware.
“Roughly 33 months is the minimum time between EM-1 and EM-2,” Gerstenmaier said. “That’s driven by the fact that we have to change the Mobile Launch Platform to accommodate the 40-foot taller rocket associated with EM-2.”
Regardless of what the agency ultimately decides to do, however, Gerstenmaier said that this study gives NASA an opportunity to step back and evaluate what it is doing on EM-1.
“This is a great opportunity for us to step back, reflect on what we’re doing, look at the overall plan again and see if [there are] any changes we want to make [while] moving forward,” Gerstenmaier said.
Derek Richardson has a degree in mass media, with an emphasis in contemporary journalism, from Washburn University in Topeka, Kansas. While at Washburn, he was the managing editor of the student run newspaper, the Washburn Review. He also has a website about human spaceflight called Orbital Velocity.