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Posted
17 minutes ago, Raider5678 said:

https://www.dailystar.co.uk/news/world-news/673349/NASA-430000mph-Parker-Solar-Probe-Sun-speed-London-New-York-video

If this probe succeeds, it'll be traveling at a whopping 430,000 MPH.

For reference, Voyager 1, the current fastest space probe, is traveling at 38,610 MPH.

 

I'll forgive you because you are American but that paper is a POS tabloid. Note this quote: "It is expected to operate for seven years orbiting the hottest star in the solar system."

Posted
32 minutes ago, StringJunky said:

I'll forgive you because you are American but that paper is a POS tabloid. Note this quote: "It is expected to operate for seven years orbiting the hottest star in the solar system."

Which is bunk, because it's obviously going to be orbiting the coldest star in the solar system.

Posted (edited)
9 minutes ago, swansont said:

Which is bunk, because it's obviously going to be orbiting the coldest star in the solar system.

No, you are both wrong. It will orbit the smallest star in the solar system.

 

And, slightly better than the Star article is this from wikipedia.

Or this from NASA.

Edited by Area54
Posted (edited)
14 minutes ago, Raider5678 said:

Ah, okay.

it's a largely smutty paper littered with plenty of  fake news, mixed with the normal stuff presented in a usually biased way. I don't doubt the project you reported on though.

What would the delta V be like at that speed?

Edited by StringJunky
Posted (edited)
26 minutes ago, StringJunky said:

it's a largely smutty paper littered with plenty of  fake news, mixed with the normal stuff presented in a usually biased way. I don't doubt the project you reported on though.

What would the delta V be like at that speed?

 

I have no idea.

However, you also have to note it can simply fall and gain massive speed at the periapsis. 

 

Edited by Raider5678
Posted
10 minutes ago, Raider5678 said:

I have no idea.

However, you also have to note it can simply fall and gain massive speed at the periapsis. 

 

But the article implies it will travel at that speed for the whole trip, which I assume is a mistake. 

 

Posted
3 minutes ago, swansont said:

But the article implies it will travel at that speed for the whole trip, which I assume is a mistake. 

 

It's news media, I'll forgive them for not being rocket scientists.

 

But obviously yeah, the rocket won't be traveling at the same speed the entire trip.

As it exits Earths orbit I assume it'll start slowly falling towards a closer orbit around the sun, or possibly a swing by.

Either way, at it's closest point to the sun is where it'll be moving fastest.

Posted
9 hours ago, StringJunky said:

it's a largely smutty paper littered with plenty of  fake news, mixed with the normal stuff presented in a usually biased way. I don't doubt the project you reported on though.

What would the delta V be like at that speed?

Delta V from what?    The stated velocity matches that for something launched from Earth and placed in a solar orbit with a perihelion of 6.9 million km (the closest approach for the probe given by the NASA site) and an aphelion at Earth's orbit.   The Delta V needed to insert it into this solar orbit (beyond that needed to escape Earth's gravity) would be ~47,550 mph As you would have to get the probe down to about 20,000 mph from Earth's orbital velocity of 67,500 mph to allow it to fall in that close to the Sun. 

The velocity gained while traveling from aphelion to perihelion would be ~410,000 mph. 

This solar orbit would have a period of ~138 days, so it would take the probe ~ 69 days to reach perihelion from the Earth. 

These numbers assume a "direct shot" approach, but the actual trajectory is designed with a Venus fly-by which actually will increase this to 93 days and actually puts the firsts perihelion further out than the closest approach that the probe will later make. 

Subsequent orbits will also have Venus flybys(7 of them) which will alter the orbit further reducing the period and lowering the perihelion.

This shows the changing trajectory of the probe over the course of its mission.

16-00815_MissionDesign.png

 

Posted
8 hours ago, Janus said:

Delta V from what?    The stated velocity matches that for something launched from Earth and placed in a solar orbit with a perihelion of 6.9 million km (the closest approach for the probe given by the NASA site) and an aphelion at Earth's orbit.   The Delta V needed to insert it into this solar orbit (beyond that needed to escape Earth's gravity) would be ~47,550 mph As you would have to get the probe down to about 20,000 mph from Earth's orbital velocity of 67,500 mph to allow it to fall in that close to the Sun. 

The velocity gained while traveling from aphelion to perihelion would be ~410,000 mph. 

This solar orbit would have a period of ~138 days, so it would take the probe ~ 69 days to reach perihelion from the Earth. 

These numbers assume a "direct shot" approach, but the actual trajectory is designed with a Venus fly-by which actually will increase this to 93 days and actually puts the firsts perihelion further out than the closest approach that the probe will later make. 

Subsequent orbits will also have Venus flybys(7 of them) which will alter the orbit further reducing the period and lowering the perihelion.

image

I was picturing several manoeuvres involving changes of velocity but that picture clarifies it. Cheers.

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