My short bio: Hi Reddit! I'm NASA Launch Director Tim Dunn, and we're launching the Cyclone Global Navigation Satellite System (CYGNSS) spacecraft into Space on December 12th at 8:24am EST.

CYGNSS will use a constellation of eight small satellites to vastly improve extreme weather prediction, particularly in hurricanes. The launch itself begins with the drop of the Pegasus rocket carrying the CYGNSS spacecraft –that’s where I come in! But this rocket won't launch vertically like a normal rocket...It will launch horizontally from underneath the belly of an L-1011 aircraft out over the Atlantic Ocean!

Here are a few photos of the aircraft and rocket carrying the spacecraft:

I'll be live here to answer your questions beginning at 2:00pm EST today. AMA!

My Proof:

That's all the AMA we have time for today! Great [email protected] session, everyone. I got some really good questions! Remember to watch the launch of the Pegasus rocket carrying the CYGNSS Spacecraft on December 12th at 8:24am EST live on NASA TV @, and lookout for more AMA's from Kennedy Space Center in the future!


Comments: 94 • Responses: 21  • Date: 

guzinya18 karma

What are the benefits from launching this way? Fuel savings? The ability to potentially launch from anywhere?

What are the drawbacks?

Have you ever played Kerbal Space Program?

NASAKennedy17 karma

The Pegasus vehicle is very flexible in launching small spacecraft to a variety of orbits. We chose it because of the perfect match with spacecraft size and weight. Only Pegasus limitation is that it can't launch spacecraft heavier than about 500 kg. Never played KSP. Gotta try it!

PraiseStalin7 karma

Star Trek or Star Wars?

NASAKennedy12 karma

Star Trek!

DecadentBeast7 karma

Did you have to make a decision on choosing to launch in December vs earlier in the year (since hurricane season is mostly over for the states and I imagine all that data this year would have been interesting) or was the launch timing more based on when CYGNSS was ready? How long do you hope CYGNSS will be functioning in orbit?

NASAKennedy9 karma

Hurricane Matthew pushed the launch date from mid-November to mid-December. But we can launch the mission on any day of the year. Getting the eight CYGNSS microsatellites on-orbit and operational prior to next year's hurricane season beginning June 1st is very important to our science team. So a December 12th launch date works great. The plan is for CYGNSS to operate for 2 years on orbit, then we hope to have an option (funding $) to extend the mission.

anddingowashisnameoh6 karma

Hey Tim! Thanks for doing the AMA.

What determined CYGNSS using eight micro-satellites as opposed to...fewer or more than eight?

How long will it take to deploy CYGNSS once the Pegasus rocket drops from the carrier plane?

One major influence that led you to your current field?

Thanks a bunch and best wishes on the launch. My birthday is the 12th so I'll consider the CYGNSS launch my birthday candle. Cheers!

NASAKennedy5 karma

Happy early Birthday! NASA Launch Services Program and Orbital ATK hope to light your biggest candle on 12 December! CYGNSS can operate effectively using only 6 satellites. So 8 was chosen to give both better coverage and a bit of margin should we experience a problem with one or two of the microsatellites.The last pair of satellites will deploy from Pegasus at 14 minutes 34 seconds after drop from the L-1011 aircraft. Major influence: Captain Kirk - a was a real Star Trek nerd growing up.

Claydough893 karma

This topic seems extremely interesting to me. I spent 4 years as a missileer in the Air Force and am startinbg a program to attain a pilots license in April.

What are some of the benefits/drawbacks to using this method of launch?

Between a manned mission to Mars and commercial space flights, which do you predict will occur first?

NASAKennedy2 karma

Thank you for your service to our nation! Best of luck in your pilot training. The benefits of Pegasus are the low-cost and launch flexibility. We can effectively launch anytime and almost anywhere worldwide due to the L-1011 service as the mobile "1st Stage" of the launch system. Commercial space flights will occur first -- should begin within the next couple of years.

anticitizen23 karma

So Pegasus can launch from Hawaii, California, or Florida? Why Florida this time?

NASAKennedy5 karma

Florida launch site for CYGNSS due to the required science orbit. We're tracking hurricanes with CYGNSS so we need to see the area of the globe +/- 35 degrees north and south of the Equator.

anticitizen23 karma

What are the big differences from your job's perspective between launching a Pegasus vs a rocket on a pad?

NASAKennedy4 karma

For a launch from a fixed pad, the countdown clock is very important. However, due to the dynamic nature of aircraft, we manage the launch countdown primarily by the position of the plane, L-1011, relative to the "drop box" where we need to release the Pegasus so it begins it's climb to orbit from the right starting point. It is a very different and exciting countdown experience!

captmrwill2 karma

Who is 'Matthew' (as written on the rocket)?

NASAKennedy4 karma

Our NASA LSP Mission Manager for CYGNSS, Aly Mendoza-Hill, named this rocket Matthew in honor of Hurricane Matthew which just passed Florida this Fall. It's a great tie-in with the hurricane winds mission of CYGNSS.

FunkMastaPost2 karma

Is Rush your favorite band?

NASAKennedy1 karma


AppleSolver2 karma

  1. What are the different technologies that work inside GYGNSS that define who it is?
  2. How are you going to monitor it so precisely? Weather always changes.

NASAKennedy1 karma

CYGNSS was developed by Southwest Research Institute along with the University of Michigan and contains cutting-edge technology. The constellation of CYGNSS microsatellites will downlink their data to ground stations 24/7.

crashalido2 karma

How will the CYGNSS array work together with, or complement, the new GOES-R (GOES 16) satellite or European satellites like the Sentinels?

NASAKennedy1 karma

The science data from CYGNSS will be available to weather researchers and will certainly be used in conjunction with weather data available from other space-based platforms such as GOES, Jason-3, NPP, etc.

Tato70692 karma

What is the coolest part of your job?

NASAKennedy1 karma

The people I work with are terrific! The job we get to do of launching rockets is indescribable! Definitely launch day is the coolest; sometimes stressful as we are working technicalities during the countdown but always rewarding to see ignition and the start of another amazing science mission for our nation!

bearpics162 karma

Let's be real. You decided to launch it from an airplane because it looks adorable, didn't you.

My real question: The moment the rocket is released from the airplane, what kind of effect does it have on the airplane itself? Does it go all crazy for a few seconds?

NASAKennedy2 karma

Definitely a dynamic moment for the aircrew in the L-1011 but they are well trained and highly experienced so not too crazy. As you can imagine, the aircraft wants to get away form the soon-to-be-ignited rocket quickly, so the aerodynamic effect of dropping that much mass aids in that plan.

michaeldeimeke1 karma

As the NASA Launch Director, do you provide your final "go" to the Orbital ATK Director as part of the countdown procedure? Who goes to the Range for launch clearance, you or him/her?

NASAKennedy1 karma

Hi Cruise! Great to see you on Reddit!

Chtorrr1 karma

What would you most like to tell us that no one has asked about yet?

NASAKennedy1 karma

The CYGNSS launch team is comprised of highly-skilled space professionals from NASA, Orbital ATK, Southwest Research Institute, the University of Michigan, and the United States Air Force, and they are amazing!

Nashad1 karma

What is different about this spacecraft that allows it to improve weather prediction abilities so vastly?

NASAKennedy1 karma

CYGNSS will use GPS signal reflectivity from the water's surface to measure hurricane wind speed from space for the the first time ever!

gnarcophagus1 karma

I'm graduating in the spring with as BS in Aerospace Engineering, any advice?

NASAKennedy3 karma

Great degree! Best of luck! You will love this career field. If you want to design spacecraft and launch vehicles, look at the opportunities from the big Aerospace companies like Boeing, Lockheed Martin, Orbital ATK, ULA, SpaceX, etc. NASA is a great opportunity for space exploration; especially deep space and robotic scientific missions. Early in your career, learn your job well and discover the specific areas that excite you!

NeutronStars141 karma

What new technology in telescopes are you most excited about?

NASAKennedy1 karma

Not a telescope guy.

Zan_H1 karma

What are your thoughts on oatmeal cookies?

NASAKennedy3 karma

Add chocolate chips!

LemonyLollipop1 karma

Are there specially trained pilots for this sort of thing that NASA has employed or can just any pilot do?

NASAKennedy1 karma

Specially trained pilots from Orbital ATK.

seanspotatobusiness1 karma

How many stages is the launch/insertion separated into? What means of propulsion are attached to the individual satelites themselves? How long after launch will the final satelite be in it's intended final orbit. Thanks for any insight!

NASAKennedy1 karma

Pegasus has 3 stages. The 8 microsatellites do not have any active propulsion on-board. Final pair of satellites will be released from Pegasus at 14 minutes 34 seconds after drop from L-1011.