Everything You Ever Wanted to Know About a Weightless Flight on NASA's "Vomit Comet"

What is the "Vomit Comet"?

First things first – what is this, so called, “Vomit Comet” and how does it work?  The Vomit Comet is the nickname for an aircraft that simulates zero gravity (well, technically microgravity, aka 10^-6 gravity).  NASA uses this plane for research and education purposes. Those who qualify can conduct microgravity research onboard the Vomit Comet through the NASA Flight Opportunities Program.  And the best part? NASA foots the bill for the flight. It’s an incredible program that provides a crucial research opportunity for space-bound projects and get young students (like myself) to pursue STEM majors.

But how does a plane create a microgravity environment?  Well, it flies in parabolic motion kind of like a roller coaster.  The top half, or the “hump,” of the plane’s parabola is the part where the people inside feel microgravity, for about ~25 seconds.  The bottom half of the parabola is the part when the people inside feel hypergravity, or 1.8 times gravity, for about ~20 seconds.  Throughout our flight, we did this about 40 times. Weightless. Twice Gravity.  Weightless. Twice Gravity. Etc.  Hence “Vomit Comet.”

Now – let’s jump into how NASA prepares humans for this little “ride.”


1. NASA's Safety Briefing

Safety first! At NASA’s Ellington Field, the home of the NASA Vomit Comet, safety is of utmost concern. The most important thing to remember – know where everything is at all times. You cannot lose anything, because even a little ballpoint pen can cause $200,000+ worth of damage if it gets sucked into an engine. And that’s not including the potential danger it would pose to humans! So they take this stuff very seriously.  If there is even a screwdriver missing from the NASA tool box – the ZeroG flight will not take off until they find it!

Bottom line – hold on to your belongings people, or you’re going to have a ton of anxious weightless hopefuls hating your guts.


2. Motion Sickness Briefing and Anti-Motion Sickness Medicine!

Next up – how not to barf on the Vomit Comet. Essentially your body gets confused when it feels something that is counter intuitive to what it sees. For example, you feel like you are floating / not moving, but you look out the window and you see the aircraft is actually diving toward the ground.  Your body's response? It barfs.  Like that will make it better, or something.

The NASA/Zero-G folks teach you how to avoid this bodily confustion by giving you some tips and tricks like – lay down during the hypergravity portion and don’t move your neck! Always (try) to stay right side up! Your body will be really confused when your feet are on the ceiling and you are not, in fact, falling toward the ground. Also, doing flips could make you sick, but they are really fun, so they might be worth it.

NASA gives you 2 options to ward off motion sickness: a pill or an injection.  They are both like a more intense version of Dramamine.  NASA highly recommends the injection because you will start to feel the effects quicker and it is out of your system faster (and some say it works better).  After taking the medicine, you feel dizzy because it slows down your inner ear fluid, which helps you balance yourself.  So don't make any quick motions on the ground after taking these meds because your body is little dumb and you might fall down.


3. The Flight!

About an hour after you take your meds, you are ready to board the flight! NASA gives you a pre-flight briefing to prepare you for what you are about to experience, which goes a little like this:

  1. Get on the ZeroG airplane - the inside of the plane is gutted out except for ~10 rows in the back of the plane.  The gutted out part is padded from the ceiling to the ground like an insane asylum.  In microgravity, you will be everywhere so it's important that no matter where your body is thrown (even if it's on the ceiling) that you have a soft landing. 
  2. Take off like a normal airplane - You sit in the passenger seats, and take off normally.
  3. 10 minutes to prepare your experiment - Once the plane reaches a certain altitude, everyone gets up from their seats and gets their microgravity experiments ready!
  4. Hypergravity to start - once everyone is ready, the NASA/Zero-G folks will announce that we are beginning the hypergravity portion.  During this time, you should lay on your back and not move your head around to prevent motion sickness!
  5. Microgravity!!!!! - After 30-40 seconds of hypergravity, the NASA/Zero-G folks will say "coming out" which means we are about to start floating! The NASA/Zero-G pro's are there to make sure you don't hurt yourself while floating around the cabin and trying to do science.  
  6. Repeat - This cycle of hypergravity, microgravity, hypergravity, microgravity is repeated ~30 times (this can differ depending on the research program)
  7. Lunar and Martian Gravity - Lastly, the plane will go into lunar and martian parabolas (about 5 each) which provide the feeling of 1/6 gravity and 3/8 gravity respectively.  This is when you can jump around the aircraft like you are walking on the moon/Mars.  It's awesome.
  8. Get back in your seats for landing - Once all of the parabolas are over, you must return to your seats for landing.  

The entire flight takes about 2 hours, and it will probably be the most fun 2 hours of your lifetime.  What does it feel like?  You know the feeling you get when you go over a hump on a roller coaster and your stomach drops?  Well it's that exact feeling for 25 seconds.  Float to the ceiling, push off from one side of the plane to another, do an assisted flip in mid-air - it's all incredibly fun and I don't think I stopped smiling and laughing the entire time.

If you are a researcher (student or private) and would like to conduct research in microgravity, learn more about NASA's Flight Opportunities Program here.

Note:  If you are one of those people who is particular about which aircraft is dubbed the "Vomit Comet" -> This name was given to the first aircraft that NASA trained astronauts in during Project Mercury.  The nickname stuck and was carried over to NASA's successor airplanes used for this purpose (KC-135, and DC-9). And yes, I do realize that this flight was taken on a 727, an aircraft owned by ZeroG.  However, NASA is still footing the bill for this flight.  I think of the "Vomit Comet" as no one particular aircraft, but rather as any aircraft used for microgravity research purposes.  It's also a very recognizable name, which helps non-aerospace gurus understand what researchers are doing here.