It's almost time for the first-ever test flight of the Orion spacecraft, NASA's human deep space exploration vehicle. Watch the live feed and follow along with us as we work through the countdown, launch, test flight, and landing! Update: The launch is scrubbed; next attempt Friday 7:05 am EST.


Top image: Orion launches today! Credit: NASA/Kim Shiflett

A Delta IV Heavy rocket with Orion mounted to the top sits at the Mobile Service Tower at Space Launch Complex 37, Cape Canaveral, Florida, undergoing launch preparations on December 3, 2014. Image credit: NASA/Bill Ingalls


This article will start as a skeleton outline, filling in with details, quirky things that come up, hiccups, and everything else that catches our interest as the night goes on. You can catch up on the nitty-gritty details of what to expect during the flight here, or check out this artist's concept of the whole flight plan (or this version made in the Kerbal Space Program). Please join us in the discussion, and don't be shy about politely pointing out mistakes, or tipping us off to news you catch before us!

If for some reason our livefeed embed isn't working for you, you can also catch the video livefeed here, the mobile feed, or an audio-only feed here.


While the basic form-factor of Orion looks a lot like the Apollo missions that carried humans to the moon, the technology has undergone significant improvements in the intervening decades.

Apollo vs. Orion. Image credit: NASA


Almost 200 people are involved in the test flight this morning, with crew from NASA, Lockheed Martin, and United Launch Alliance (ULA) working together from control rooms around the country.

Orion Program Management team at the United Launch Alliance control center reviewing vehicle status. Image credit: ULA


Spaceflight involves a lot of checklists to make sure everything is as ready as it can be to give the spacecraft the greatest possible chances for success.


Weather: Conditions at the launch location have improved to a 70% Go for the test flight. Some concerns remain about precipitation and high winds on the flight path, but the chances of a coastal shower during the launch window have dropped. Temperatures are expected to stay well above freezing, reducing concern.

12:37am Gantry pushback: Mobile Service Tower, the support structure for the rocket, has pushed back, leaving Orion and the Delta IV Heavy exposed on the launch pad. The tower has sheltered the rocket and spacecraft from the elements since rolling out to the pad, and provided full access for checks and preparations. (Missed it? Watch the video here!)


Gantry rollback shortly after midnight EST. Image credit: NASA/Bill Ingalls;United Launch Alliance;United Launch Alliance


The Mobile Service Tower weighs over 4 million kilograms, and needs to slowly crawl 100 meters away to leave the pad clear for flight. No technical concerns have been reported that will impact the test flight.

Looking up the Delta IV Heavy rocket as the support gantry pulls back. Image credit: United Launch Alliance

Fuelling: The rocket is Go for fuelling. The hydrogen is loaded first, then the oxygen. Both are chilled for cryogenic tanking: hydrogen is cooled to -252°C, while oxygen is cooled to -183°C. The fuel evaporates and vents after fuelling, so a small trickle is constantly added to keep the rockets topped-up. The rockets will consume the fuel in just 4 minutes.


Gaseous oxygen venting in clouds around the fuelled rocket. Image credit: NASA;NASA

The constant evaporation means that hydrogen pools on the pad. While a small red flame licks at the side of the pad to constantly burn it off, reducing detonation hazard, enough remains to lead to this rocket's unnerving tendency to set itself on fire during ignition. So, don't be worried when flames lick up the boosters and even set them smoldering during the launch!


The hydrogen flare stack is the red flame to the side of the launch pad, burning off excess hydrogen fuel that evaporated and escaped the rocket. Image credit: NASA


5:10 am: A problem has come up with a valve on the oxygen booster core. The problem is familiar to the ULA team from previous Delta launches, and should not impact the flight.

5:42 am: Orion's batteries are charging well.

On the causeway "tailgaiting NASA-style." Image credit: @nzpeavler

6:05 am Steering checks on the rocket have checked out.

6:27 am Everything is good to go so far. Weather is clear in both the launch and landing locations, and no major technical issues are being worked for Orion or for the rocket.


6:46 am: Orion and Delta are ten minutes away from being ready to launch, yet the scheduled launch time isn't until 7:05 am. This is because the launch sequence has a built-in 15 minute hold for final go/no go checks. The hold will expire at 7:01 am. If everything looks good, Orion will enter the terminal launch countdown. If a problem comes up, the team has 2 hours, 39 minutes to fix anything before the launch window expires.

6:55am The hold is being extended due to a "fouled range," where a boat is in the rocket range area within the danger area. The Delta rocket also requires additional time for conditioning for the second stage. No confirmation that it's the same boat that delayed the Antares launch, but we know it is.


Orion and the Delta rocket at dawn during the final built-in hold. Image credit: NASA


7:04 am The new T-0 time is still to-be-determined based on how long it takes to clear out the boat and get the rocket happy. Once the hold does expire, we'll be on the terminal 4 minute countdown.

7:06 am: New T-0 launch time is set at 7:17 am Eastern Time. Orion is now on internal power.


Orion backlight by sunrise. Image credit: NASA

7:11 am We're in the final Go/No-Go checks. Launch director has been given permission to launch.


7:14 am The launch hit a ground wind violation, meaning the winds at ground level are too strong for a safe launch. Wind has been good all morning, so this was a gust of wind that tripped a sensor; assuming another gust doesn't come up, the new launch time should be in just a few minutes. This is a delay, not an abort: if the winds die down within the launch window closes at 9:44 am, the launch countdown will start back up and send Orion on its way.


7:26 am The rocket has been recycled and reset for launch. The launch team is recommending making a note of the wind violation, and moving on with deciding if the wind has subsided enough to set a new T-0 launch time.

Orion makes up for delays by looking gorgeous.

7:30 am Orion is backed out to the T-9 minutes configuration, back on external power to save battery. Everything is still Go with the spacecraft and rocket as soon as winds die down.


7:38 am Turns out that even rocket scientists don't have much to do while waiting on wind. The liquid oxygen and liquid hydrogen — LOX & LH2 — vapours spilling down the rocket are the only indicators that the livefeeds haven't crashed and we're still watching and awaiting for Orion to blast off.

7:45 am A new T-0 launch time has been set at 7:55 am.

7:48 am Orion is back on internal power. Although we here at io9 believe that epic rocket launches are always justification for being late to work or taking extended breaks, if you do need to head out on your commute, NASA has a mobile livestream here.


7:51 am We're in the terminal 4-minute countdown (again).

Orion and Delta awaiting favourable weather to launch. Image credit: NASA

7:54 am Another automatic sensor trip put Orion back on hold. The spacecraft is being recycled and placed in safe condition (again). In addition to "Space is hard," it's time to start up, "Waiting for launch is dull." Can everyone on the Space Coast just go form a living windbreak around the launch pad, please?


An inversion is over the launch site causing the wind gusts. It is forecast to break up within the next 45-60 minutes, which would still leave plenty of time within the launch window for Orion to blast off this morning.

8:03 am The launch commit criteria is a spacecraft-specific set of rules for each launch. The wind gusts are exceeding the 21 knot (11 meters/second) limit set by United Launch Alliance for the Delta IV.


Teams waiting at control rooms and space centers around the country. Image credits: NASA;NASA;NASA; Kelley Miller

8:11 am Delays have been substantial enough that the common booster cores now require topping up with additional liquid hydrogen and oxygen to bring the propellant tanks back up to launch pressure.

8:16 am Wind has died down (again): a new T-0 launch time is set for 8:26 am. The crews are going through re-arming the rocket for launch, and will be conducting final checks prior to entering the terminal countdown at 8:22 am.


It's now full daylight on a beautiful morning with an hour left in the launch window. Image credit: NASA

8:24 am Hold due to a valve problem. Two fill and drain valves on the liquid oxygen hydrogenbooster tanks failed to close, one on the starboard port tank and one on the common core. The spacecraft is once again on external power as they work the problem. (Or, in NASA-speak, the "exception," which will be worked by the "anomaly team.")


8:33 am Based on last time they had this problem, the solution to the sticky valves is to open and close them a whole bunch of times in a row. The three valves on the first stage of the tanks will all be cycled open and closed five times to see if they unstick. Sometimes, troubleshooting in rocket science is a lot like troubleshooting anything else! (Amusingly, cycling the valves was part of troubleshooting the crowdfunded ISEE spacecraft recovery this summer.)

9:00 am All the fill and drain valves on the liquid oxygen tanks are now functional, as is the starboard liquid hydrogen valve. The team is still discussing if the valves are now functional on the port and central hydrogen valves.


9:06 am Valves on the liquid hydrogen tank are still being wonky, so the team will pressurize the propellent tanks, holding it at that pressure, then releasing it to see if that fixes the problem.

9:15 am The drain valves continue to be uncooperative. If they are not fixed before the launch window expires at 9:44 am, the next window is Friday morning at the same time, then Saturday about five minutes later.

8:26 am Flipping things open and closed didn't work. Fill-and-holding didn't work. But flipping them really, really quickly just might!


The winds continue to be gusty and irritating, so instead of having an automated sensor tripping a hold, the team is disabling the alarm and switching to manually monitoring. The actual launch constraint criteria have also been adjusted, ranging from 19.5 to 23.5 knots (10 to 12 meters per second) depending on the direction.

A new T-0 launch time has been set for 9:44 am, the very last moment in the launch window.


8:32 am: Between gusting winds and sticky valves, we're pushed right at the end of a launch window. We still don't know if the fill and drain valve problem is fixed, and are in the final hold. If the valves get fixed and both the spacecraft and rocket pass final polls one more time, we'll exit the hold at T-4 minutes at 9:40 am.

8:38 am: The crew was unable to fix the valve problem in time. The launch has been scrubbed, and set on a 24-hour recycle. The next launch attempt will be on Friday morning. Assuming the valve gets fixed, we'll be back on with your live coverage as Orion toys with our hearts.

While it's disappointing to have a highly-anticipated launch scrubbed, it's still so, so much better than having a gust of wind or a sticky valve crash the rocket.



This is a historic launch at a historic location: Orion is on Pad 37B, the same launch pad where the first American uncrewed moon mission launched in the 1960s.


President Kennedy on a press event at the Space Launch Complex. Image credit; NASA (via @DavidHitt)

If the launch is on-time, the International Space Station will be over the Kamchatka Peninsula and unable to watch the launch. The astronauts will similarly be out of position to watch the splashdown, so Expedition 42 will be following along on the livestream, just like most of the rest of us.

This will be the eighth launch for the ULA Delta IV Heavy rocket. This is the most powerful rocket currently available in the American space program:


Counting down to Orion will be the first time the new countdown clock will be used. The LED video clock is an upgrade over the previous version which used 40-watt lightbulbs.

New coutdown clock. Image credit: Jack Fischer

Orion is NASA's first spacecraft intended to build an Earth-independent future of human space exploration. NASA Administrator Charles Bolden advocates for embracing the risk of Orion:


Spaceflight is risky — this could go catastrophically wrong any time from launch through the actual test flight. But even if things go wrong, this will be a learning experience with valuable data gathered to inform future exploration, and to build capacity for future missions.

Test Flight

Orion will climb past Low Earth Orbit, into the Van Allen belts and fifteen times higher than the International Space Station during its test flight. While this is an uncrewed test flight, it's the highest any spacecraft designed to carry humans has gone since the moon landings.


Flight path for Exploration Test Flight 1, the first test flight of the Orion spacecraft. Image credit: NASA


Orion will splash down off the coast of Baja California in the Pacific Ocean, where it will be recovered by Navy ship USS Anchorage.


Crews preparing in the Orion splashdown and recovery zone off the coast of Baja California. Image credit: NASA


The splashdown will hopefully be documented by a drone currently cruising the recovery zone.

View from the uncrewed drone prepared to document Orion's splashdown. Image credit: NASA

Orion may be left powered on after splashdown to increase its thermal signature for recovery efforts. The decision on how long to leave it powered up will happen in the last chunk of the test flight.


Last update: Gusts of winds and sticky valves delayed the Orion launch. Unable to fix the problem before the launch window expired at 9:44 am, the launch attempt was scrubbed and held for 24 hours. Assuming the valve problems can be fixed, the next launch attempt will be on Friday morning starting at 7:05 am Eastern Time.