Tag Archive: Block II

Nov 09 2017

Progeny Mk5 Block I Flight 2 Analysis

Last week’s launch was the first complete flight to space and back of our new Block I design, which primarily features more powerful first and second stage solid-fuel booster engines. Despite the incredible record-setting apokee of 493km and being able to recover the payload afterwards (barely), many problems became apparent that have needed to be addressed. In this report we will first cover the details of the flight, then look into solutions for the problems that occurred and finally talk about how we plan to move forward.

The Flight

After delays and a scrub of the initial launch time due to weather issues, the rocket was finally launched off the pad at 01:58:00.03 UTC under command of the Automated Flight Control System. The first stage solid fuel booster kicked in at 67.226kN of thrust to propel the rocket at an initial rate of 4Gs off the pad in order to put enough aerodynamic force into effect to keep the rocket’s nose from lifting too high. Beginning at 85° the nose of the rocket reached a maximum pitch of 86.935° at 2 seconds after launch, well-within limits. Burning fuel at a rate of 39.089kg per second, the 0.625m booster propelled the rocket up to 788.124m/s over the course of its 20.42 second burn, topping out at 76.422kN of thrust. The dynamic pressure at flame-out was 139.299kPa, by far the highest sustained so far by a complete stack of the Mk5. The booster was decoupled as planned 1 second after flame-out was detected, which is when the first flight anomaly occurred.

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Nov 01 2017

Progeny Mk5 Block I & II Launches Halted for Program Review

Although the second flight of the Mk5 Block I was an incredible success, reaching nearly 500km up into space (more than twice what we hoped for), it has also brought to light numerous issues that will need to be resolved. We consider ourselves to be extremely lucky in being able to recover this rocket & until we feel confident we can do it again we won’t be launching any more. This also extends to the more-powerful Block II variant, which is directly dependent on the success of the Block I. In addition to any technical and engineering issues, the very nature of the Mk5 program will need to be rethought now that we have an idea of just how powerful the newer boosters are. We planned for the Block I to service LKO & have trouble pushing payloads beyond 250km. The Block II was therefore the heavy-lift variant that would allow science data to be gathered beyond this distance.

Today the recovered third stage was carefully dismantled, large sections were fused together due to the heat from re-entry, but the data onboard was accessed and confirmed mostly intact, which still marks this as a successful flight. These next few days will be spent analyzing the telemetry and science data to aid in determining what our next steps will be. As the launch video released earlier shows, there were some problems during ascent that will need to be addressed.

Until we release our full report on the flight, the next Block I launch that was scheduled for 11/7 has been pushed back to no earlier than 11/22, while the Block II launch has been pushed back to no earlier than December. We very much hope to get at least one Block II off before the operational year ends on 12/15!

Oct 12 2017

Introducing the Progeny Mk5 Block II

The Mk5 Block II has been finalized! This bigger variant of the Mk5 adds power with 4 strap-on boosters and an extended liquid fuel tank. The strap-on boosters are an upgraded version of the Mk1-B booster, which can now output 21.795kN of thrust at sea level with greater efficiency as opposed to 18.75kn. Upon liftoff all 5 lower boosters will ignite for a total thrust-to-weight ratio of 5, which is 1G greater than the Mk5 Block I to help compensate for both the increased mass & length, which could cause the rocket to stand up a bit more as lift at the nose will have a greater torque effect with the nearly 1m extension. The strap-on boosters will burn for just over 6 seconds before being decoupled to leave the core booster firing with enough thrust to continue pushing at 3+Gs for another 15 seconds before it too is discarded. The third stage booster has been set to a TWR of 2 at 9km ASL and once ignited will burn for 15.5 seconds. The stage four liquid booster will be able to burn well over a minute or two depending on how its throttle is set during ascent.

The added power of the Block II should allow us to extend our reach into space beyond the boundaries of Low-Kerbin Orbit (LKO) which extends from 70km – 250km above Kerbin’s atmosphere. Although the rocket is almost 500kg heaver than the Block I it still manages to deliver almost 1km/s more deltaV, which when modeled with the highest Mk5 trajectory pushed our apokee out beyond 300km – and that was assuming a coast period up into the vacuum of space after the LF/O engine burnt out so with a continuous burn from the Block II’s double-capacity liquid fuel tanks we may even be able to get higher.

All this speculation will be put to the test when we launch our first Block II, which is currently scheduled to occur no earlier than November 15th. The launch date & time will be finalized later this month after we see how the Block I performs, as any defects found with it will also most likely affect the Block II. Despite the 4 added boosters Lead Engineer Simon reports that the VAB will only need two additional days to install them, giving us roughly a 2.5 week minimum turnaround between Block II launches as opposed to the 2 weeks needed for the Block I. Additional details can be viewed in the blueprint below.