Featured image credit: Astra/John Kraus
Launch Window/Lift Off Time | NET December 15, 2020 – 19:00-22:00 UTC | 11:00-14:00 PT |
|---|---|
Mission Name | Orbital Launch Attempt 2 |
Launch Provider | Astra |
Customer | Astra |
Rocket | Rocket 3.2, the second iteration of Astra’s Rocket 3 series |
Launch Location | Launch Pad 3B, Pacific Spaceport Complex in Kodiak, Alaska |
Payload mass | Up to 25 kg (55 lb) |
Where are the satellites going? | To a Low Earth Orbit (LEO) of 380 km, at an inclination of 98.1° |
Will they be attempting to recover the first stage? | No, this is not a capability of Astra. |
Where will the first stage land? | The first stage will crash into the Pacific Ocean |
Will they be attempting to recover the fairings? | No, this is not a capability of Astra. |
Are these fairings new? | Yes |
How’s the weather looking? | We don’t know Astra’s weather criteria for launch, but the weather in Kodiak doesn’t look too good. |
This will be the: | – 1st test launch of Rocket 3.2 – 2nd test launch this year |
Where to watch | Unfortunately Astra won’t have a live webcast for this launch, but they will post live updates on their Twitter. |
What does all this mean?
Astra will launch its orbital-class rocket Rocket 3.2 from Launch Pad 3B, Pacific Spaceport Complex in Kodiak, Alaska. This launch can happen somewhere in the launch window that extends from December 7 to December 18 with a daily launch window opening up at 19:00 UTC and closing at 22:00 UTC. Rocket 3.2 will mark Astra’s second orbital launch attempt ever.
The Mission
After a failure of the guidance system and a following shut down of the engines in the early stages of the first stage burn of Rocket 3.1 back in September 2020, Astra is back at the launch pad. Rocket 3.2 is Astra’s second iteration of its Rocket 3 series and will again feature no payload as it is a test launch in Astra’s three launch campaign with the goal to finally reach orbit. There will only be additional sensors and instruments on the second stage that are required for data gathering during the different phases of the flight.
For the previous launch attempt Astra has set some goals they wanted to achieve. They aimed towards a nominal first stage burn and considered everything after main engine cut off (MECO) as additional goodies. They only achieved some of those milestones, but the data they’ve gathered was valuable enough that they might have raised their expectations for this launch. But since there is no information on that available at this time, we can only speculate.
Mission Timeline
| T-1h15min | Start of final pre-launch procedure |
| T-45min | Propellant load begins |
| T-20min | Propellant load complete |
| T-15min | Entering terminal count |
| T-/+0s | Ignition! |
| T+3s | Lift Off! |
| T+5s | Roll program initiated |
| T+25s | Vehicle clears range |
| T+38s | Gravity turn |
| T+57s | Maximum aerodynamic pressure (Max Q) |
| T+2min 3s | Begin to throttle down the engines |
| T+2min 22s | Main engine cut off (MECO) |
| T+2min 25s | Fairing separation |
| T+2min 29s | Stage separation |
| T+2min 33s | Second stage engine ignition |
| T+8min 32s | Second engine cut off (SECO) |
| T+8min 35s | Payload deployment signal |
The Rocket 3.2 Launch Vehicle
Rocket 3.2 is Astra’s second iteration of their third version of their small-sat launch vehicle. The Rocket 3 series is Astra’s orbital rocket series. With a height of 11.6 m (38 ft), a diameter of 1.32 m (4.3 ft) and a payload capacity of 25 kg to a 500 km Sun-Synchronous Orbit (SSO), it is in the same class of small-sat launch vehicles as Rocket Lab’s Electron.
This two-stage rocket is powered by RP-1 and LOx. The first stage will make use of five electric-pump-fed Delphin engines that will produce a total thrust of ~145 kN (~32,500 lbf) at liftoff. The second stage is powered by a single pressure-fed Aether engine that will produce 3.1 kN (700 lbf) of thrust in a vacuum. Since Astra is a rather secretive company, they have not released any technical information about their engines, such as ISP (Specific Impulse), TWR (Thrust to Weight Ratio), or combustion chamber pressure. The aluminum body and tanks of Rocket 3.2 have a similarity to SpaceX’s Starship prototypes, with its welded stacked rings of stainless steel.
Another unique characteristic is that Astra’s Rocket 3 series rockets fit into a standard shipping container and can be towed by a truck. To set up the rocket on its mobile launch structure, it only takes a handful of ground support staff and about a week to go through vehicle checks, a wet dress rehearsal and the launch readiness review. Astra’s goal for the future is to bring the time required to set up the rocket down to under 24 hours. Therefore, it can meet the needs of some special customers who require a rapid launch schedule for their payloads.
Differences between Rocket 3.1 and Rocket 3.2
After the failure earlier this year, Astra held a post launch briefing in which they explained that there are only minor hardware differences between Rocket 3.1 and Rocket 3.2. The biggest change between the two different rockets will be in Software. Especially in the guidance software since this was the part of the rocket that failed during Rocket 3.1‘s launch.
Loss of Rocket 3.1
After liftoff of Astra’s first orbital launch attempt on September 12, 2020 at 04:19 UTC, the team on the ground send the signal to shut down the engines in the early stages of the first stage burn. This was caused by the rocket drifting off enough from the planned trajactory due to a software issue in the guidance system. Up until this point the rocket had performed nominally and also the Flight Termination System (FTS) worked as intended. Rocket 3.1 fell back down and exploded on impact. Due to the small size of Astra’s rockets they don’t require a pyrotechnical FTS, which would add complexity and cost to the rocket. Instead, they just shut down the engines, let it fall back down to earth and clean up whatever is left of the rocket.
Loss of Rocket 3.0
After a wet dress rehearsal as part of a pre-launch test in March, Astra’s Rocket 3.0 suffered from a catastrophic anomaly. This incident lead to the loss of Rocket 3.0. The anomaly was caused by a valve which was stuck open during de-tanking of the rocket. Fortunately, nobody was harmed during this incident, and only Astra’s hardware was damaged. Astra went back to the drawing board and tried to recreate the problem with the valve which has previously been tested thousands of times. After months of finding the root to the problem, Astra implemented three levels of redundancy in order to prevent another anomaly.
Additional Information on Astra
If you want to find out more about Astra, check out their Twitter or the previous Prelaunch Preview. There you will find more information on Astra’s company history and their team.
