Tuesday, December 30, 2008

Hints for a Venus New Frontiers Proposal

The following is from a NASA request to industry for information on a parachute system for several possible probes for a New Frontiers Venus mission. (The original post is at SpaceRef.)

It would seem unlikely to me that a single mission could include all the elements listed below. However, the hints are interesting to ponder.

NASA is developing potential proposals for the upcoming New Frontiers Program Announcement of Opportunity (2009) that involve multiple strategies for Venus exploration. Many of the suggested mission concepts aim to deliver scientific payloads through the atmosphere of Venus to the surface. Four options are being considered that likely require parachute systems: a lander, a deployed balloon reconnaissance platform, a large probe, and a smaller probe. A key component of these options is a Venus parachute subsystem. It is highly desirable that this subsystem have a strong heritage to previous planetary missions, and especially those implemented in the past 15 years. This announcement supersedes any previously released RFI. Each of the four primary options has a unique set of elements, as summarized below.

For the Venus Lander, the backshell will be ejected and a single canopy will be deployed at an altitude of ~ 65-67 km and a velocity of ~Mach 0.8. The atmospheric entry interface heat shield will be jettisoned after parachute deployment. The Venus Lander is to touch down in approximately 50 minutes from parachute deployment at an impact velocity of less than 10 m/s. The entry vehicle mass (backshell, Lander, and heat-shield) will be 800 to 1000 kg, and the Lander mass will be no more than 695 kg.

For the Balloon Reconnaissance Platform, the backshell will be ejected and a single canopy will be deployed by a mortar at an altitude of ~ 60 km and a velocity of Mach 0.8 to 1.2. The heat shield will be dropped, and approximately 10 seconds after the parachute is deployed, inflation of the balloon will begin. Approximately 30 seconds after the parachute is deployed, the Balloon Reconnaissance Platform will be released from the parachute. The speed at release should be less than 50 m/s.

For the Larger Probe, a mortar will deploy a pilot parachute which will carry off the backshell and deploy the main canopy. This system will utilize a 300-500 kg total flight system mass and deploy the parachute at ~ 60-65 km for later release around 50km. The parachute subsystem will consist of two basic groupings of components: a mortar deployed pilot parachute for backshell separation and main parachute deployment; and a main parachute for heat shield separation and descent speed control. Deployment will occur at a velocity of ~Mach 0.8. The heat shield will be jettisoned approximately 5 seconds after main parachute deployment. The main parachute will be jettisoned at an altitude of 15 to 30 km.

For the Small Probe, a mortar will deploy a single canopy which will carry off the backshell and extract the Small Probe pressure vessel from the aeroshell. This system will utilize a 85-120 kg total flight system mass and deploy the parachute at ~ 60-65 km for later release around 50 km. The parachute subsystem will consist of two basic groupings of components: a mortar deployed pilot parachute for backshell separation and main parachute deployment; and a main parachute for heat shield separation and descent speed control. Other components are similar to the large probes described above.

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