2020 era Orion CEV in Venus orbiter mission

[JonClarke]

Flybys are fine for unmanned missions where cost, technology, or velocity constraints limit the options.<br /><br />Manned missions are so much more expensive than unmanned ones I can't see the point given the very limited opportunities they offer for scientific return. Especially they would add very little to what we know already from unmanned misions to Venus (or Mars).<br /><br />Of course this does not mean they should not be done. But their rationale must be sort elsewhere. Technology and confidence building and testing is one I think. A symbolic guesture would be another.<br /><br />Jon <div class="Discussion_UserSignature"> <p><em>Whether we become a multi-planet species with unlimited horizons, or are forever confined to Earth will be decided in the twenty-first century amid the vast plains, rugged canyons and lofty mountains of Mars</em>  Arthur Clarke</p> </div>

 

[mithridates]

Back to the main topic again: hope this hasn't been mentioned yet but it seems quite a bit of the mission could be done ahead of time to reduce weight. 5,000 kg for atmospheric entry probes could certainly be put into orbit around Venus much earlier than the manned modules as well as part of the scientific payload to Venus orbit. <div class="Discussion_UserSignature"> <p>----- </p><p>http://mithridates.blogspot.com</p> </div>

 

[j05h]

<i>> Back to the main topic again:</i><br /><br />CEV to an Earth-crossing NEO is much more compelling than a Venus orbitter. Most of the Venus science can be done w/ robots and the view is boring. <br /><br />josh <div class="Discussion_UserSignature"> <div align="center"><em>We need a first generation of pioneers.</em><br /></div> </div>

 

[gunsandrockets]

"hope this hasn't been mentioned..."<br /><br />Yeah, I did on the first page of the thread, but thanks for bringing it back up!<br /><br />" ...yet but it seems quite a bit of the mission could be done ahead of time to reduce weight. 5,000 kg for atmospheric entry probes could certainly be put into orbit around Venus much earlier than the manned modules as well as part of the scientific payload to Venus orbit."<br /><br />Of the manned mission payload mass of 120,000 lb., 1/3 is the atmospheric probes and the science payload. I advised splitting that mass off from the manned mission. The unmanned component should be sent to low Venus orbit prior to the manned mission departure.<br /><br />It doesn't matter to the unmanned equipment how slowly it reaches Venus. Slow travelling but energy saving methods could be employed: low delta V transfer orbits, lunar-flyby gravity assist, electric-engine Earth departure propulsion, slow aerobraking from high Venus orbit into a low circular Venus orbit.<br /><br />There is also no reason why the unmanned equipment couldn't be broken down into small bite sized chunks. Each landing probe or Venus orbiting observers could be launched with it's own launch vehicle such as an Atlas V, Falcon IX or Soyuz. Launch vehicles already in mass production in 2020 would cut down the cost of launch and loss of a single launch would not doom the entire mission. Using separate launches also encourages international co-operation by opening up more operational aspects of the entire mission. I could easily see ESA probes launched with Soyuz rockets.<br /><br />Another mass saving but riskier change in mission design is to send the Earth return stage to the planned Venus parking orbit prior to the manned mission launch. The same energy saving techniques for the unmanned equipment could also be employed for delivery of the Earth return stage.<br /><br />By the time all is said and done, these methods might cut in half the mass of the manned spacecraft compo

 

[gunsandrockets]

"Back to the Venus topic, figures we would need so much time. I guess an NEO mission will have to prove the endurance part. Once we go to Venus, we might as well enter orbit. Sounds like the trip won't take any longer or require much more Delta V."<br /><br />Actually a Venus orbiter mission is much more difficult than a Venus flyby mission. A Venus orbiter mission could last as long as 565 days compared to a flyby mission lasting 365 days. The mass needed for an Apollo level technology Venus flyby mission is only 118 tonnes in LEO. Using the same technology a Venus orbiter mission needs at least 424 tonnes!<br />

 

[willpittenger]

The mission that evolved into Apollo 8 started out as a flyby. In fact, the Soviets had already sent Zonds around the Moon with animals on board. This was one reason why Apollo 8 was moved up. It was also why the mission ceased to be a "simple" flyby. <div class="Discussion_UserSignature"> <hr style="margin-top:0.5em;margin-bottom:0.5em" />Will Pittenger<hr style="margin-top:0.5em;margin-bottom:0.5em" />Add this user box to your Wikipedia User Page to show your support for the SDC forums: <div style="margin-left:1em">{{User:Will Pittenger/User Boxes/Space.com Account}}</div> </div>

 

[willpittenger]

I know. I was thinking in terms of scale. Instead of 1-2 months that I had been hoping for, we need at least a year. I must have forgotten how long it took Magellan to reach Venus. <div class="Discussion_UserSignature"> <hr style="margin-top:0.5em;margin-bottom:0.5em" />Will Pittenger<hr style="margin-top:0.5em;margin-bottom:0.5em" />Add this user box to your Wikipedia User Page to show your support for the SDC forums: <div style="margin-left:1em">{{User:Will Pittenger/User Boxes/Space.com Account}}</div> </div>

 

[gunsandrockets]

"Flybys are fine for unmanned missions...Manned missions are so much more expensive than unmanned ones I can't see the point given the very limited opportunities they offer for scientific return. Especially they would add very little to what we know already from unmanned misions to Venus (or Mars)."<br /><br />The real science payoff of a manned Venus orbiter mission is the combination of the manned presence allowing real-time control of partnered unmanned probes. The potential of a manned flyby mission permitting much of the same partnership is worth thinking about. I am really beginning to warm to the idea of a manned Venus flyby mission.<br /><br />The orbiter mission spends 40 days in orbit, two of which are relatively close to Venus due to the highly elliptical parking orbit around Venus. A flyby mission would only spend hours close to Venus and maybe only a few days on the approach and retreat from Venus during which radio delay to Venus probes would be similar to Earth-to-moon communications. The thing is that even during the short time that a flyby mission is close to Venus might be all that is neccessary to achieve most of what a Venus orbiter could gain by real-time control of unmanned probes.<br /><br />The closest approach of a Venus flyby could allow virtually instantaneous communications, short enough delay to allow real-time control of the landing of an unmanned probe to a more dangerous surface area of Venus. If that lander had a rover, the flyby crew could control the rover for the very likely short lifespan of the rover under the very harsh conditions of Venus.<br /><br />The practical aspects of mounting a manned Venus mission may be the make or break factor when comparing a flyby to an orbiter mission. By my reconning a Venus orbiter mission will need at least two Ares V launches + one Ares I launch for the manned spacecraft, separate MLV launches for all the unmanned probes, and use of inflatable habitation module technology plus development of a

 

[bdewoody]

The base line for a NASA mission is funding. A manned mission to Venus would need the approval of Congress and for Congress to approve a mission to Venus Mr. John Q. Public would have to be interested. I have read all of the proposals cited here and even though most have scientific merit none seem to me to have what it takes to get enough public support to get Congress to jump on board.<br /><br />I think for the foreseeable future manned missions outside of earth orbit will be reserved for destinations that have permanent base and potential commercial possibilities, ie. the moon, Mars and possibly some of the larger asteroids.<br /><br />Good luck on getting your funding. <div class="Discussion_UserSignature"> <em><font size="2">Bob DeWoody</font></em> </div>

 

[mithridates]

The only way I can see the public getting interested is if part of the reason is to learn more about the effect of CO2 on climate. That's an issue that most people care about.<br />Or if another country decides they want to do it first of course. <div class="Discussion_UserSignature"> <p>----- </p><p>http://mithridates.blogspot.com</p> </div>

 

[bdewoody]

If the U.S. public was truly interested in CO2 emission reduction they would quit buying gas hog trucks and SUVs and would let go of their fear of nuclear power plants.<br /><br />Heck the Kennedys opposed the development of wind generators off of Cape Cod. It seems everybody suffers from the NIMBY syndrome. <div class="Discussion_UserSignature"> <em><font size="2">Bob DeWoody</font></em> </div>

 

[mithridates]

I'm not making the argument that the American public will be ready to fund a mission based on these reasons, but rather that I don't see any better way to tie it into the lives of ordinary people than that.<br />Plus, you know it's much easier to kind of fund a mission with tax dollars that don't get seen in the first place than to make an actual sacrifice. <div class="Discussion_UserSignature"> <p>----- </p><p>http://mithridates.blogspot.com</p> </div>

 

[willpittenger]

<blockquote><font class="small">In reply to:</font><hr /><p>If the U.S. public was truly interested in CO2 emission reduction they would quit buying gas hog trucks and SUVs and would let go of their fear of nuclear power plants.<p><hr /></p></p></blockquote><br />Fission is not in my mind that much better than fossil fuels. Now if <b><i><font color="yellow">fusion</font>/i></i></b> power technology was ready, then we would have something. Places like Los Angeles would no longer need water from the Colorado River. Instead, they could make all the fresh water they need cheaply from sea water. <div class="Discussion_UserSignature"> <hr style="margin-top:0.5em;margin-bottom:0.5em" />Will Pittenger<hr style="margin-top:0.5em;margin-bottom:0.5em" />Add this user box to your Wikipedia User Page to show your support for the SDC forums: <div style="margin-left:1em">{{User:Will Pittenger/User Boxes/Space.com Account}}</div> </div>

 

[gunsandrockets]

"The base line for a NASA mission is funding. A manned mission to Venus would need the approval of Congress and for Congress to approve a mission to Venus Mr. John Q. Public would have to be interested. I have read all of the proposals cited here and even though most have scientific merit none seem to me to have what it takes to get enough public support to get Congress to jump on board."<br /><br />Congress is already on board. What do you think the huge bipartisan vote in favor of the VSE was all about? If one Venus mission takes the same effort as a single moon landing mission (likely the case for a Venus flyby mission) do you really think congress will all of a sudden say, STOP!<br /><br />For congress to do such a thing when the Ares V are launching twice a year would be the equivalent of congress micromanaging every Shuttle mission today. VSE is about manned exploration of the solar system, and so far no one has proclaimed some area is off limits!<br /><br /><br />