NASA contracted with SpaceX and Boeing to develop private spacecraft capable of ferrying astronauts to the International Space Station. SpaceX’s Crew Dragon and Boeing’s CST-100 Starliner are currently undergoing testing to prove the designs work as expected, and to ensure the spacecraft meet NASA’s safety standards. Tests are performed by the companies with NASA engineers on-hand to certify the results and offer advice for fixing problems
To test the environmental control and life support systems (ECLSS), SpaceX built the ECLSS Module, a test-version of the Crew Dragon with a transparent floor panel so engineers can observe the systems in operation.
Testing of the ECLSS Module at SpaceX headquarters in Hawthorne, California. Credit: SpaceX
Ongoing tests in the ECLSS Module are helping SpaceX engineers understand how the systems work in practice, not just computer simulations and analysis. In an earlier development phase, engineers were sealed within the module to breathe a mix of oxygen and nitrogen provided by the automated systems. Testing is now getting more sophisticated, pushing the spacecraft to ensure that it can maintain temperature, humidity, carbon dioxide and oxygen levels, and cabin pressure appropriate for humans under any circumstances.
The spacecraft runs through simulations of expected environments for the entire mission: launch, orbit, docking to the space station, and splashdown. It’s also undergoing more extreme simulations of emergency situations, including testing the fire suppression system without depriving astronauts of critical life support functions.
Engineers working within the ECLSS Module during testing of the SpaceX Crew Dragon environmental control and life support systems. Credit: SpaceX
Boeing uses boilerplate spacecraft, a non-functional model of the same size and mass as the Starliner for its parachute tests. In February, a helium balloon lifted the boilerplate Starliner 12,000 meters above White Sands Missile Range in New Mexico. When released from the balloon, a yellow stabilization weight hanging from the bottom of the capsule kept it on target and boosted acceleration, so it descended at nearly 500 kilometers per hour.
Once it reached target speeds to mimic reentry, the Starliner boilerplate deployed two drogue parachutes for stabilization at 8,500 meters, a pilot parachute at 3,600 meters, and finally the main parachute at 2,500 meters. All the parachutes successfully deployed, followed by the capsule shedding its heat shield at 1,400 meters. The sequence successfully slowed the capsule enough to touchdown on the desert floor without damage, kicking up a cloud of dust.
Interior of the ECLSS Module used for testing the environmental control and life support systems for SpaceX’s Crew Dragon. Credit: SpaceX
Landings during commercial crew transport missions will contain one final stage not included in this test sequence. Right before landing, the Starliner capsule will deploy air bags to cushion the crew from the shock of landing. In theory, soft landings on solid ground will allow Boeing to send each Starliner on ten missions by avoiding saltwater contamination from an ocean splashdown.
Deployed parachutes seen from the top hatch of Boeing’s CST-100 Starliner. Credit: Boeing
Target dates for first flights of Crew Dragon and Starliner have been pushed back every few months, but are currently anticipated for mid-2018 with regular missions to the space station starting by late 2018. Both spacecraft will launch from Florida: Starliner will lift off on an Atlas V rocket from Space Launch Complex 41 on Cape Canaveral Air Force Station, and Crew Dragon on a Falcon 9 rocket from Launch Pad 39A at Kennedy Space Center.