All About Space spoke to NASA’s Dr. Cathy Olkin – Deputy Project Scientist for the New Horizons mission and project scientist for the ‘Ralph’ instrument, which is taking colour images of Pluto.
AAS: A decade is a long wait from launch to target – you must be on tenterhooks.
Dr. Olkin: Yes – I’ve been working on this for more than a decade and even just back in January when it turned 2015, I had to pinch myself! Then when we were getting Ralph data down from the spacecraft I was like “I can’t believe we’re seeing Pluto, I can’t believe Pluto’s getting bigger!” I feel so excited that this day has come but it feels so surreal because we’ve waited for it for so long.
AAS: We can imagine that around this time it’s like Curiosity’s ‘7 minutes of terror’ as the lander made its final descent.
DR Olkin: Right. I think we already had that with our reset, so I think we’re good from here! [laughs]
AAS: As a planetary scientist with a particular interest in the icy worlds of the outer Solar System, this mission must be especially exciting for you. What do you hope to discover about Pluto?
DR Olkin: Many things – but by looking at Pluto we are looking at the best studied example of bodies in the Kuiper belt, in the third zone of the Solar System past the giant planets, where there’s all these icy and rocky bodies that we didn’t really know existed. We knew of Pluto since 1930, but it wasn’t until the early 1990’s that the additional Kuiper Belt objects were being seen. So, what I’m really excited about is to get a really close-up look at Pluto, the composition of its surface and its atmosphere. To look at Pluto’s moons and have examples of what these bodies look like in this outer region of the Solar System.
AAS: How big is the window for taking really detailed photos?
DR Olkin: Really detailed images started about a month ago when were seeing resolutions better than we could see from the ground. So from that point forward we were learning new things every day. Of course, we travel almost a million miles every day so each day is better than the last. But I would say we’ve had more than a month where we’ve seen detail on the surface that we haven’t seen and at closest approach, it would be our highest resolution data. So, looking with different instruments… the encounter’s been going for weeks in my mind.
AAS: Can we expect New Horizons to return images of Pluto as detailed as those taken by Voyager 1, for example, on its 1979 flyby of Jupiter?
Dr Olkin: At closest approach we are going to map the hemisphere at better than half a kilometre per pixel – it’s revolutionary. In addition there are regions that we’ll map even better than that, at 200, 100 metres per pixel and there are certain regions that we’ll get around 70 metres per pixel. As Alan Stern likes to say, “If we could move New York City to Pluto, we could count the ponds in Central Park.” That’s a great way of explaining it because a lot of people can relate to that.
AAS: You’re project scientist for the Ralph instrument – New Horizon’s ‘eye’. Can you tell us a bit about it?
DR Olkin: So there are two camera’s, the LORRI camera and the Ralph camera. Ralph gives us colour imaging of the targets we’re looking at: Pluto, Charon and the small moons. It’s also two instruments in one, the colour camera and also an infrared spectrometer. So we can look in the infrared and learn about the composition of the surface of these bodies, so it’s really a two-for-one.
AAS: Pluto’s a very cold Solar System object – do you hope to penetrate the surface and look for subsurface oceans?
DR Olkin: We won’t be penetrating the surface, but we have thought that there might be an ocean beneath the surface. There could be geological manifestations of that on the surface – we might be able to infer something about that. But we won’t be probing deep into Pluto to see that.
AAS: How long will New Horizons be operational for after its fly-by?
DR Olkin: New Horizons can go on for years and years and years. I can’t give you a solid answer on that but the spacecraft is healthy, the instruments are healthy, we have a good power supply that’s working well. So there’s no end in sight.
AAS: So potentially, it could go on into interstellar space like Voyager 1 + 2?
DR Olkin: Yes. That’s right – it’s what we expect will happen.
AAS: Pluto was ‘downgraded’ to dwarf planet status in 2006, months after New Horizon’s launch. Did this affect the mission at all?
DR Olkin: It didn’t affect the mission and you’ll find that many of the mission scientists still refer to Pluto as a ‘planet’. It really didn’t change how I look at Pluto at all. I’ll still call it a ‘planet’ when I’m discussing it, that feels like the right name to me.
AAS: So it was just a technicality and business as usual for you?
DR Olkin: Certainly from my perspective. I call it a planet – it has an atmosphere and moons – it seems like a planet to me.
You can also learn more on National Geographic Channel’s Mission Pluto, which premiers Sunday 12th July at 8pm.